- added GroupModel
- updated API.md
added "PUT /users/<username>"
changed UserService::create($username, $email, $password) to UserService::create(UserModel $model)
removed UserService::getByUsername()
some fixes
added gitignore
added handling of 403 with Dispatch's error()
optimized imports
added Services\Response\Impl\AccessDeniedImpl
removed some \Exception-catcher
added some debug information