public IEnumerable<ValidationResult> Add(UserViewModel model)
        {
            var userEntity = new UserEntity {Age = model.Age, Firstname = model.Firstname, Lastname = model.Lastname};

            if (_validator.IsValid(userEntity))
            {
                //Save entity
            }

            return _validator.ValidationResult;
        }
        public ActionResult Index(UserViewModel model)
        {
            var userService = new UserService();

            var validationResults = userService.Add(model);

            foreach (var validationResult in validationResults)
            {
                ModelState.AddModelError(validationResult.MemberNames.First(), validationResult.ErrorMessage);
            }

            return View(model);
        }