Added placeholder for documentation

docs/api/authentication.md

@@ -0,0 +1,63 @@
+# Authentication
+
+JWT-based authentication system for the Letzshop Import API.
+
+## Overview
+
+The API uses JSON Web Tokens (JWT) for authentication. Users must register, login to receive a token, then include the token in subsequent requests.
+
+## Authentication Flow
+
+1. **Register** - Create a new user account
+2. **Login** - Authenticate and receive JWT token
+3. **Use Token** - Include token in API requests
+
+## Endpoints
+
+### Register User
+```http
+POST /api/v1/auth/register
+Content-Type: application/json
+
+{
+  "email": "user@example.com",
+  "username": "testuser",
+  "password": "securepassword123"
+}
+```
+
+### Login
+```http
+POST /api/v1/auth/login
+Content-Type: application/json
+
+{
+  "username": "testuser",
+  "password": "securepassword123"
+}
+```
+
+Response:
+```json
+{
+  "access_token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9...",
+  "token_type": "bearer",
+  "expires_in": 86400
+}
+```
+
+## Using Authentication
+
+Include the JWT token in the Authorization header:
+
+```http
+GET /api/v1/product
+Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9...
+```
+
+## User Roles
+
+- **User** - Basic access to own resources
+- **Admin** - Full system access
+
+*This documentation is under development.*