diff --git a/db/migrations/001_initial_schema.sql b/db/migrations/001_initial_schema.sql
new file mode 100644
index 0000000..538aefc
--- /dev/null
+++ b/db/migrations/001_initial_schema.sql
@@ -0,0 +1,235 @@
+-- SeCu Database Schema
+-- Version: 1.0.0
+-- Date: 2026-02-20
+
+-- Enable UUID extension
+CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
+
+-- ============================================
+-- ORGANIZATIONS (Multi-Tenancy)
+-- ============================================
+CREATE TABLE organizations (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    name VARCHAR(255) NOT NULL,
+    slug VARCHAR(100) UNIQUE NOT NULL,
+    settings JSONB DEFAULT '{}',
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_organizations_slug ON organizations(slug);
+
+-- ============================================
+-- USERS
+-- ============================================
+CREATE TYPE user_role AS ENUM ('chef', 'disponent', 'mitarbeiter');
+
+CREATE TABLE users (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    org_id UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+    email VARCHAR(255) NOT NULL,
+    password_hash VARCHAR(255) NOT NULL,
+    role user_role NOT NULL DEFAULT 'mitarbeiter',
+    first_name VARCHAR(100) NOT NULL,
+    last_name VARCHAR(100) NOT NULL,
+    phone VARCHAR(50),
+    avatar_url VARCHAR(500),
+    created_by UUID REFERENCES users(id) ON DELETE SET NULL,
+    managed_by UUID REFERENCES users(id) ON DELETE SET NULL,
+    active BOOLEAN DEFAULT true,
+    last_login TIMESTAMP WITH TIME ZONE,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    
+    UNIQUE(org_id, email)
+);
+
+CREATE INDEX idx_users_org ON users(org_id);
+CREATE INDEX idx_users_role ON users(org_id, role);
+CREATE INDEX idx_users_managed_by ON users(managed_by);
+
+-- ============================================
+-- ORDERS (Aufträge)
+-- ============================================
+CREATE TYPE order_status AS ENUM ('draft', 'published', 'in_progress', 'completed', 'cancelled');
+
+CREATE TABLE orders (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    org_id UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+    number SERIAL,
+    title VARCHAR(255) NOT NULL,
+    description TEXT,
+    location VARCHAR(255),
+    address TEXT,
+    client_name VARCHAR(255),
+    client_contact VARCHAR(255),
+    status order_status DEFAULT 'draft',
+    start_time TIMESTAMP WITH TIME ZONE,
+    end_time TIMESTAMP WITH TIME ZONE,
+    required_staff INTEGER DEFAULT 1,
+    special_instructions TEXT,
+    created_by UUID NOT NULL REFERENCES users(id) ON DELETE RESTRICT,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_orders_org ON orders(org_id);
+CREATE INDEX idx_orders_status ON orders(org_id, status);
+CREATE INDEX idx_orders_dates ON orders(org_id, start_time, end_time);
+
+-- ============================================
+-- ORDER ASSIGNMENTS (Zuweisungen)
+-- ============================================
+CREATE TYPE assignment_status AS ENUM ('pending', 'confirmed', 'declined', 'completed');
+
+CREATE TABLE order_assignments (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    order_id UUID NOT NULL REFERENCES orders(id) ON DELETE CASCADE,
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    status assignment_status DEFAULT 'pending',
+    note TEXT,
+    confirmed_at TIMESTAMP WITH TIME ZONE,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    
+    UNIQUE(order_id, user_id)
+);
+
+CREATE INDEX idx_assignments_order ON order_assignments(order_id);
+CREATE INDEX idx_assignments_user ON order_assignments(user_id);
+
+-- ============================================
+-- AVAILABILITY (Verfügbarkeit)
+-- ============================================
+CREATE TABLE availability (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    date DATE NOT NULL,
+    available BOOLEAN NOT NULL DEFAULT true,
+    time_from TIME,
+    time_to TIME,
+    note TEXT,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    
+    UNIQUE(user_id, date)
+);
+
+CREATE INDEX idx_availability_user_date ON availability(user_id, date);
+
+-- ============================================
+-- TIMESHEETS (Stundenzettel)
+-- ============================================
+CREATE TYPE timesheet_status AS ENUM ('pending', 'approved', 'rejected');
+
+CREATE TABLE timesheets (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    order_id UUID REFERENCES orders(id) ON DELETE SET NULL,
+    work_date DATE NOT NULL,
+    start_time TIME,
+    end_time TIME,
+    hours_worked DECIMAL(5,2),
+    photo_url VARCHAR(500),
+    status timesheet_status DEFAULT 'pending',
+    approved_by UUID REFERENCES users(id) ON DELETE SET NULL,
+    rejection_reason TEXT,
+    approved_at TIMESTAMP WITH TIME ZONE,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_timesheets_user ON timesheets(user_id);
+CREATE INDEX idx_timesheets_order ON timesheets(order_id);
+CREATE INDEX idx_timesheets_status ON timesheets(status);
+CREATE INDEX idx_timesheets_date ON timesheets(work_date);
+
+-- ============================================
+-- MODULES (Modularer Aufbau)
+-- ============================================
+CREATE TABLE modules (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    name VARCHAR(100) UNIQUE NOT NULL,
+    display_name VARCHAR(255) NOT NULL,
+    description TEXT,
+    is_core BOOLEAN DEFAULT false,
+    default_config JSONB DEFAULT '{}',
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE TABLE organization_modules (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    org_id UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+    module_id UUID NOT NULL REFERENCES modules(id) ON DELETE CASCADE,
+    enabled BOOLEAN DEFAULT true,
+    config JSONB DEFAULT '{}',
+    enabled_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    
+    UNIQUE(org_id, module_id)
+);
+
+CREATE INDEX idx_org_modules ON organization_modules(org_id);
+
+-- ============================================
+-- AUDIT LOGS
+-- ============================================
+CREATE TABLE audit_logs (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    org_id UUID REFERENCES organizations(id) ON DELETE CASCADE,
+    user_id UUID REFERENCES users(id) ON DELETE SET NULL,
+    action VARCHAR(100) NOT NULL,
+    entity_type VARCHAR(100),
+    entity_id UUID,
+    old_values JSONB,
+    new_values JSONB,
+    ip_address INET,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_audit_org ON audit_logs(org_id);
+CREATE INDEX idx_audit_user ON audit_logs(user_id);
+CREATE INDEX idx_audit_entity ON audit_logs(entity_type, entity_id);
+CREATE INDEX idx_audit_date ON audit_logs(created_at);
+
+-- ============================================
+-- REFRESH TOKENS
+-- ============================================
+CREATE TABLE refresh_tokens (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    token_hash VARCHAR(255) UNIQUE NOT NULL,
+    expires_at TIMESTAMP WITH TIME ZONE NOT NULL,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_refresh_tokens_user ON refresh_tokens(user_id);
+CREATE INDEX idx_refresh_tokens_expires ON refresh_tokens(expires_at);
+
+-- ============================================
+-- UPDATED_AT TRIGGER
+-- ============================================
+CREATE OR REPLACE FUNCTION update_updated_at()
+RETURNS TRIGGER AS $$
+BEGIN
+    NEW.updated_at = NOW();
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER update_organizations_updated_at BEFORE UPDATE ON organizations
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_users_updated_at BEFORE UPDATE ON users
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_orders_updated_at BEFORE UPDATE ON orders
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_availability_updated_at BEFORE UPDATE ON availability
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_timesheets_updated_at BEFORE UPDATE ON timesheets
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_org_modules_updated_at BEFORE UPDATE ON organization_modules
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
diff --git a/db/migrations/002_seed_modules.sql b/db/migrations/002_seed_modules.sql
new file mode 100644
index 0000000..37ede6c
--- /dev/null
+++ b/db/migrations/002_seed_modules.sql
@@ -0,0 +1,18 @@
+-- SeCu Module Seed Data
+-- Version: 1.0.0
+
+-- Core Modules (können nicht deaktiviert werden)
+INSERT INTO modules (name, display_name, description, is_core, default_config) VALUES
+('core', 'Basis-System', 'Authentifizierung und Benutzerverwaltung', true, '{}'),
+('orders', 'Auftragsverwaltung', 'Erstellen und Verwalten von Aufträgen', true, '{}');
+
+-- Optionale Module
+INSERT INTO modules (name, display_name, description, is_core, default_config) VALUES
+('timesheets', 'Stundenzettel', 'Zeiterfassung mit Foto-Upload', false, 
+ '{"require_photo": true, "auto_calculate_hours": true}'),
+('availability', 'Verfügbarkeit', 'Mitarbeiter-Verfügbarkeitsplanung', false, 
+ '{"allow_partial_day": true}'),
+('notifications', 'Benachrichtigungen', 'Push/E-Mail Benachrichtigungen', false, 
+ '{"email_enabled": true, "push_enabled": false}'),
+('reports', 'Berichte', 'Auswertungen und Statistiken', false, '{}'),
+('developer', 'Entwickler-Panel', 'Fernverwaltung und Modul-Management', false, '{}');
diff --git a/docs/database-schema.md b/docs/database-schema.md
new file mode 100644
index 0000000..f1625dd
--- /dev/null
+++ b/docs/database-schema.md
@@ -0,0 +1,453 @@
+# SeCu - Datenbank-Schema
+
+## ER-Diagramm
+
+```mermaid
+erDiagram
+    organizations ||--o{ users : has
+    users ||--o{ users : manages
+    users ||--o{ orders : creates
+    users ||--o{ orders : assigned_to
+    users ||--o{ availability : reports
+    users ||--o{ timesheets : submits
+    orders ||--o{ timesheets : has
+    orders ||--o{ order_assignments : has
+    users ||--o{ order_assignments : assigned
+    modules ||--o{ organization_modules : configured_in
+    organizations ||--o{ organization_modules : has
+
+    organizations {
+        uuid id PK
+        varchar name
+        varchar slug UK
+        jsonb settings
+        timestamp created_at
+        timestamp updated_at
+    }
+
+    users {
+        uuid id PK
+        uuid org_id FK
+        varchar email UK
+        varchar password_hash
+        varchar role "chef|disponent|mitarbeiter"
+        varchar first_name
+        varchar last_name
+        varchar phone
+        varchar avatar_url
+        uuid created_by FK
+        uuid managed_by FK "Disponent der den MA verwaltet"
+        boolean active
+        timestamp last_login
+        timestamp created_at
+        timestamp updated_at
+    }
+
+    orders {
+        uuid id PK
+        uuid org_id FK
+        integer number "Auto-increment pro Org"
+        varchar title
+        text description
+        varchar location
+        varchar address
+        varchar client_name
+        varchar client_contact
+        varchar status "draft|published|in_progress|completed|cancelled"
+        timestamp start_time
+        timestamp end_time
+        integer required_staff
+        text special_instructions
+        uuid created_by FK
+        timestamp created_at
+        timestamp updated_at
+    }
+
+    order_assignments {
+        uuid id PK
+        uuid order_id FK
+        uuid user_id FK
+        varchar status "pending|confirmed|declined|completed"
+        text note
+        timestamp confirmed_at
+        timestamp created_at
+    }
+
+    availability {
+        uuid id PK
+        uuid user_id FK
+        date date
+        boolean available
+        varchar time_from "Optional: 08:00"
+        varchar time_to "Optional: 18:00"
+        text note
+        timestamp created_at
+        timestamp updated_at
+    }
+
+    timesheets {
+        uuid id PK
+        uuid user_id FK
+        uuid order_id FK
+        date work_date
+        time start_time
+        time end_time
+        decimal hours_worked
+        varchar photo_url
+        varchar status "pending|approved|rejected"
+        uuid approved_by FK
+        text rejection_reason
+        timestamp approved_at
+        timestamp created_at
+        timestamp updated_at
+    }
+
+    modules {
+        uuid id PK
+        varchar name UK
+        varchar display_name
+        text description
+        boolean is_core "Core modules can't be disabled"
+        jsonb default_config
+        timestamp created_at
+    }
+
+    organization_modules {
+        uuid id PK
+        uuid org_id FK
+        uuid module_id FK
+        boolean enabled
+        jsonb config
+        timestamp enabled_at
+        timestamp updated_at
+    }
+
+    audit_logs {
+        uuid id PK
+        uuid org_id FK
+        uuid user_id FK
+        varchar action
+        varchar entity_type
+        uuid entity_id
+        jsonb old_values
+        jsonb new_values
+        varchar ip_address
+        timestamp created_at
+    }
+
+    refresh_tokens {
+        uuid id PK
+        uuid user_id FK
+        varchar token_hash UK
+        timestamp expires_at
+        timestamp created_at
+    }
+```
+
+## SQL Migrations
+
+### 001_initial_schema.sql
+
+```sql
+-- Enable UUID extension
+CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
+
+-- ============================================
+-- ORGANIZATIONS (Multi-Tenancy)
+-- ============================================
+CREATE TABLE organizations (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    name VARCHAR(255) NOT NULL,
+    slug VARCHAR(100) UNIQUE NOT NULL,
+    settings JSONB DEFAULT '{}',
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_organizations_slug ON organizations(slug);
+
+-- ============================================
+-- USERS
+-- ============================================
+CREATE TYPE user_role AS ENUM ('chef', 'disponent', 'mitarbeiter');
+
+CREATE TABLE users (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    org_id UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+    email VARCHAR(255) NOT NULL,
+    password_hash VARCHAR(255) NOT NULL,
+    role user_role NOT NULL DEFAULT 'mitarbeiter',
+    first_name VARCHAR(100) NOT NULL,
+    last_name VARCHAR(100) NOT NULL,
+    phone VARCHAR(50),
+    avatar_url VARCHAR(500),
+    created_by UUID REFERENCES users(id) ON DELETE SET NULL,
+    managed_by UUID REFERENCES users(id) ON DELETE SET NULL,
+    active BOOLEAN DEFAULT true,
+    last_login TIMESTAMP WITH TIME ZONE,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    
+    UNIQUE(org_id, email)
+);
+
+CREATE INDEX idx_users_org ON users(org_id);
+CREATE INDEX idx_users_role ON users(org_id, role);
+CREATE INDEX idx_users_managed_by ON users(managed_by);
+
+-- ============================================
+-- ORDERS (Aufträge)
+-- ============================================
+CREATE TYPE order_status AS ENUM ('draft', 'published', 'in_progress', 'completed', 'cancelled');
+
+CREATE TABLE orders (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    org_id UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+    number SERIAL,
+    title VARCHAR(255) NOT NULL,
+    description TEXT,
+    location VARCHAR(255),
+    address TEXT,
+    client_name VARCHAR(255),
+    client_contact VARCHAR(255),
+    status order_status DEFAULT 'draft',
+    start_time TIMESTAMP WITH TIME ZONE,
+    end_time TIMESTAMP WITH TIME ZONE,
+    required_staff INTEGER DEFAULT 1,
+    special_instructions TEXT,
+    created_by UUID NOT NULL REFERENCES users(id) ON DELETE RESTRICT,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_orders_org ON orders(org_id);
+CREATE INDEX idx_orders_status ON orders(org_id, status);
+CREATE INDEX idx_orders_dates ON orders(org_id, start_time, end_time);
+
+-- ============================================
+-- ORDER ASSIGNMENTS (Zuweisungen)
+-- ============================================
+CREATE TYPE assignment_status AS ENUM ('pending', 'confirmed', 'declined', 'completed');
+
+CREATE TABLE order_assignments (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    order_id UUID NOT NULL REFERENCES orders(id) ON DELETE CASCADE,
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    status assignment_status DEFAULT 'pending',
+    note TEXT,
+    confirmed_at TIMESTAMP WITH TIME ZONE,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    
+    UNIQUE(order_id, user_id)
+);
+
+CREATE INDEX idx_assignments_order ON order_assignments(order_id);
+CREATE INDEX idx_assignments_user ON order_assignments(user_id);
+
+-- ============================================
+-- AVAILABILITY (Verfügbarkeit)
+-- ============================================
+CREATE TABLE availability (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    date DATE NOT NULL,
+    available BOOLEAN NOT NULL DEFAULT true,
+    time_from TIME,
+    time_to TIME,
+    note TEXT,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    
+    UNIQUE(user_id, date)
+);
+
+CREATE INDEX idx_availability_user_date ON availability(user_id, date);
+
+-- ============================================
+-- TIMESHEETS (Stundenzettel)
+-- ============================================
+CREATE TYPE timesheet_status AS ENUM ('pending', 'approved', 'rejected');
+
+CREATE TABLE timesheets (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    order_id UUID REFERENCES orders(id) ON DELETE SET NULL,
+    work_date DATE NOT NULL,
+    start_time TIME,
+    end_time TIME,
+    hours_worked DECIMAL(5,2),
+    photo_url VARCHAR(500),
+    status timesheet_status DEFAULT 'pending',
+    approved_by UUID REFERENCES users(id) ON DELETE SET NULL,
+    rejection_reason TEXT,
+    approved_at TIMESTAMP WITH TIME ZONE,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_timesheets_user ON timesheets(user_id);
+CREATE INDEX idx_timesheets_order ON timesheets(order_id);
+CREATE INDEX idx_timesheets_status ON timesheets(status);
+CREATE INDEX idx_timesheets_date ON timesheets(work_date);
+
+-- ============================================
+-- MODULES (Modularer Aufbau)
+-- ============================================
+CREATE TABLE modules (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    name VARCHAR(100) UNIQUE NOT NULL,
+    display_name VARCHAR(255) NOT NULL,
+    description TEXT,
+    is_core BOOLEAN DEFAULT false,
+    default_config JSONB DEFAULT '{}',
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE TABLE organization_modules (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    org_id UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+    module_id UUID NOT NULL REFERENCES modules(id) ON DELETE CASCADE,
+    enabled BOOLEAN DEFAULT true,
+    config JSONB DEFAULT '{}',
+    enabled_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    
+    UNIQUE(org_id, module_id)
+);
+
+CREATE INDEX idx_org_modules ON organization_modules(org_id);
+
+-- ============================================
+-- AUDIT LOGS
+-- ============================================
+CREATE TABLE audit_logs (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    org_id UUID REFERENCES organizations(id) ON DELETE CASCADE,
+    user_id UUID REFERENCES users(id) ON DELETE SET NULL,
+    action VARCHAR(100) NOT NULL,
+    entity_type VARCHAR(100),
+    entity_id UUID,
+    old_values JSONB,
+    new_values JSONB,
+    ip_address INET,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_audit_org ON audit_logs(org_id);
+CREATE INDEX idx_audit_user ON audit_logs(user_id);
+CREATE INDEX idx_audit_entity ON audit_logs(entity_type, entity_id);
+CREATE INDEX idx_audit_date ON audit_logs(created_at);
+
+-- ============================================
+-- REFRESH TOKENS
+-- ============================================
+CREATE TABLE refresh_tokens (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    token_hash VARCHAR(255) UNIQUE NOT NULL,
+    expires_at TIMESTAMP WITH TIME ZONE NOT NULL,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+CREATE INDEX idx_refresh_tokens_user ON refresh_tokens(user_id);
+CREATE INDEX idx_refresh_tokens_expires ON refresh_tokens(expires_at);
+
+-- ============================================
+-- UPDATED_AT TRIGGER
+-- ============================================
+CREATE OR REPLACE FUNCTION update_updated_at()
+RETURNS TRIGGER AS $$
+BEGIN
+    NEW.updated_at = NOW();
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER update_organizations_updated_at BEFORE UPDATE ON organizations
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_users_updated_at BEFORE UPDATE ON users
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_orders_updated_at BEFORE UPDATE ON orders
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_availability_updated_at BEFORE UPDATE ON availability
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_timesheets_updated_at BEFORE UPDATE ON timesheets
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER update_org_modules_updated_at BEFORE UPDATE ON organization_modules
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+```
+
+### 002_seed_modules.sql
+
+```sql
+-- Core Modules (können nicht deaktiviert werden)
+INSERT INTO modules (name, display_name, description, is_core, default_config) VALUES
+('core', 'Basis-System', 'Authentifizierung und Benutzerverwaltung', true, '{}'),
+('orders', 'Auftragsverwaltung', 'Erstellen und Verwalten von Aufträgen', true, '{}');
+
+-- Optionale Module
+INSERT INTO modules (name, display_name, description, is_core, default_config) VALUES
+('timesheets', 'Stundenzettel', 'Zeiterfassung mit Foto-Upload', false, '{"require_photo": true, "auto_calculate_hours": true}'),
+('availability', 'Verfügbarkeit', 'Mitarbeiter-Verfügbarkeitsplanung', false, '{"allow_partial_day": true}'),
+('notifications', 'Benachrichtigungen', 'Push/E-Mail Benachrichtigungen', false, '{"email_enabled": true, "push_enabled": false}'),
+('reports', 'Berichte', 'Auswertungen und Statistiken', false, '{}'),
+('developer', 'Entwickler-Panel', 'Fernverwaltung und Modul-Management', false, '{}');
+```
+
+### 003_seed_demo.sql
+
+```sql
+-- Demo Organization
+INSERT INTO organizations (id, name, slug) VALUES
+('11111111-1111-1111-1111-111111111111', 'Demo Sicherheit GmbH', 'demo');
+
+-- Demo Chef User (Password: Admin123!)
+INSERT INTO users (id, org_id, email, password_hash, role, first_name, last_name, phone) VALUES
+('22222222-2222-2222-2222-222222222222', 
+ '11111111-1111-1111-1111-111111111111',
+ 'chef@demo.de',
+ '$argon2id$v=19$m=65536,t=3,p=4$DEMO_HASH_REPLACE_ME',
+ 'chef',
+ 'Max',
+ 'Mustermann',
+ '+49 170 1234567');
+
+-- Enable all modules for demo org
+INSERT INTO organization_modules (org_id, module_id, enabled)
+SELECT '11111111-1111-1111-1111-111111111111', id, true FROM modules;
+```
+
+## Berechtigungsmatrix
+
+| Aktion | Chef | Disponent | Mitarbeiter |
+|--------|------|-----------|-------------|
+| **Users** | | | |
+| Disponenten anlegen | ✅ | ❌ | ❌ |
+| Mitarbeiter anlegen | ✅ | ✅ (eigene) | ❌ |
+| Alle User sehen | ✅ | ❌ | ❌ |
+| Eigene Mitarbeiter sehen | ✅ | ✅ | ❌ |
+| **Orders** | | | |
+| Aufträge erstellen | ✅ | ✅ | ❌ |
+| Aufträge bearbeiten | ✅ | ✅ (eigene) | ❌ |
+| Aufträge löschen | ✅ | ✅ (eigene) | ❌ |
+| Alle Aufträge sehen | ✅ | ✅ | ❌ |
+| Eigene Aufträge sehen | ✅ | ✅ | ✅ |
+| **Availability** | | | |
+| Verfügbarkeit melden | ✅ | ✅ | ✅ |
+| Alle Verfügbarkeiten sehen | ✅ | ✅ | ❌ |
+| **Timesheets** | | | |
+| Stundenzettel hochladen | ✅ | ✅ | ✅ |
+| Stundenzettel genehmigen | ✅ | ✅ | ❌ |
+| Alle Stundenzettel sehen | ✅ | ✅ | ❌ |
+| **Modules** | | | |
+| Module verwalten | ✅ (Dev) | ❌ | ❌ |
+
+---
+
+*Schema Version: 1.0.0*
+*Erstellt: 2026-02-20*