inital working version

CLAUDE.md

@@ -88,4 +88,11 @@ backend/           # Spring Boot application
 nginx.conf         # Reverse proxy configuration
 docker-compose.yml # Container orchestration
 .env              # Environment variables
-```
+```
+
+
+## Development Best Practices
+
+- Always create unit and integration tests where it makes sense, when creating new classes.
+- **Always check if Test Classes have to be updated after code changes**
+- When you fix an error, automatically check and see if this error might also occur in other classes.