@ResponseStatus(HttpStatus.OK)
 @ResponseBody
 @RequestMapping(
     method = RequestMethod.PUT,
     value = "/{userGroupId}",
     produces = APPLICATION_JSON_VALUE)
 public UserGroupEditDTO save(
     @RequestBody final UserGroupEditDTO dto,
     @PathVariable("userId") final int userId,
     @PathVariable("userGroupId") final int userGroupId) {
   // TODO: validate!
   save(userId, dto, userGroupService.load(userGroupId));
   return dto;
 }