public AddAppViewModel CreateNewApp()
 {
     string guid = Guid.NewGuid().ToString();
     AddAppViewModel result = new AddAppViewModel() { Guid=guid  };
     repository.Add(guid, result);
     result.Saved += OnAppSaved;
     return result;
 }
        public ActionResult AddApp(AddAppViewModel addApp)
        {
            if (!Facade.GetUser(User.Identity.Name).IsAdmin)
            {
                return NotAuthorized();
            }
            var viewmodel = EditedAppRepository.GetInstance().GetApp(addApp.Guid);
            viewmodel.AppName = addApp.AppName;
            viewmodel.Description = addApp.Description;
            viewmodel.Prerequisites = addApp.Prerequisites;
            viewmodel.Price = addApp.Price;
            viewmodel.URL = addApp.URL;
            viewmodel.Producer = addApp.Producer;
            return RedirectToAction("AddPicture", new { Guid = viewmodel.Guid });

        }