public ActionResult AddUser(UserModel model)
        {
            if (!UserModel.IsAdmin)
            {
                return(RedirectToAction("Login", "Account"));
            }

            if (ModelState.IsValid)
            {
                model.AddAccount();
                @ViewBag.ModelStateIsValid = "Ja";
                return(View());
            }
            else
            {
                @ViewBag.ModelStateIsValid = "Nee";
                return(View());
            }
        }