public void UpdateUserGroupFromInput(UserGroup model, UserGroupInput input)
		{
			model.DomainName = input.DomainName;
			model.Key = input.Key;
			model.Id = input.Id;
			model.Name = input.Name;
			model.HomepageHTML = input.HomepageHTML;
			model.City = input.City;
			model.Region = input.Region;
			model.Country = input.Country;
			model.GoogleAnalysticsCode = input.GoogleAnalysticsCode;
			var existingUsers = model.GetUsers();

			var usersToRemove = existingUsers.Where(user => !input.Users.Any(uf => uf.Id == user.Id));

			foreach (var user in usersToRemove)
			{
				model.Remove(user);
			}

			var userFormToAdd =
				input.Users.Where(userForm => !existingUsers.Any(user => user.Id == userForm.Id));
			var users = _userRepository.GetAll();

			foreach (var userForm in userFormToAdd)
			{
				var user = users.FirstOrDefault(user1 => user1.Id == userForm.Id);
				model.Add(user);
			}
		}
 public ActionResult Delete(UserGroup userGroup, Sponsor sponsor)
 {
     userGroup.Remove(sponsor);
     _repository.Save(userGroup);
     return RedirectToAction<SponsorController>(c => c.Index(null));
 }