public IHttpActionResult EnrollUsersToGroup(UsersForEnrollmentModel data)
 {
     if(data == null)
     {
         throw new ArgumentNullException("Parameter could not be null", "data");
     }
     var users = _userMapper.Map(data.UserModels);
     _enrollmentService.EnrollUsersToGroup(users, data.GroupId);
     _wordSuiteService.CopyWordsuitesForUsersByGroup(users, data.GroupId);
     _wordProgressService.CopyProgressesForUsersInGroup(users, data.GroupId);
     return Ok();
 }
 public IHttpActionResult EnrollUsersToGroup(UsersForEnrollmentModel data)
 {
     if(data == null)
     {
         throw new ArgumentNullException("Parameter could not be null", "data");
     }
     var users = _userMapper.MapCollection(data.UserModels);
     if (_enrollmentService.EnrollUsersToGroup(users, data.GroupId)
         && _wordSuiteService.CopyWordsuitesForUsersByGroup(users, data.GroupId)
         && _wordProgressService.CopyProgressesForUsersInGroup(users, data.GroupId))
     {
         return Ok();
     }
     return BadRequest("Some problem occurred!");
 }