public ActionResult Login(LoginModel model, string returnUrl)
        {
            if (!ModelState.IsValid)
            {
                return View("login", model);
            }

            // check login credentials
            if (GlobalConfig.Get().Username.Equals(model.Username, StringComparison.OrdinalIgnoreCase) && GlobalConfig.Get().Password.Equals(model.Password))
            {
                FormsAuthentication.SetAuthCookie(model.Username, false);
            }
            else
            {
                ModelState.AddModelError("failed", "Benutzername oder Passwort falsch.");
                return View("login", model);
            }

            // return to target page.
            if (Url.IsLocalUrl(returnUrl))
            {
                return Redirect(returnUrl);
            }
            else
            {
                return RedirectToAction("index", "home");
            }
        }
        public ActionResult Login()
        {
            var login = new LoginModel();

            return View(login);
        }