anchor.diff:  
               A comprehensive list of possible errors:
               - `NEED_AUTHENTICATION` if no valid session token has been supplied or the user for whom the token has been created does not exist (anymore)
  +
  ++ Response 404 (application/json)
  +    + Attributes (object)
  +        + status (string) - Textual description of the HTTP status
  +        + message (string) - Detailed error information, e.g. hint about malformed request
  +        + i18n (string) - A unique token representing above error description message; can be used for internationalization in frontends
  +
  +            A comprehensive list of possible errors:
  +            - `USER_NOT_FOUND` if the requested user does not exist in the database
           
   
   ## Create user [POST]
  
positive.code: + Response 200 (application/json)
      + Attributes (User Preview)
  
  + Response 401 (application/json)
      + Attributes (object)
          + status (string) - Textual description of the HTTP status
  
negative.code:             A comprehensive list of possible errors:
              - `NEED_AUTHENTICATION` if no valid session token has been supplied or the user for whom the token has been created does not exist (anymore)
              - `USER_INSUFFICIENT_PERMISSIONS` if the currently authenticated user has insufficient permissions (due to his rank) to perform this action
  
  + Response 404 (application/json)
      + Attributes (object)
          + status (string) - Textual description of the HTTP status
          + message (string) - Detailed error information, e.g. hint about malformed request
          + i18n (string) - A unique token representing above error description message; can be used for internationalization in frontends
  
              A comprehensive list of possible errors:
              - `USER_NOT_FOUND` if the requested user does not exist in the database
  
  + Response 406 (application/json)
      + Attributes (object)
  