public ActionResult Create(Quiz model)
        {
            if(ModelState.IsValid)
            {
                QuizRepository.Insert(model);
                QuizRepository.Save();
                return RedirectToAction("Index");
            }

            FillDropdownValues();
            return View(model);
        }
        public ActionResult AddQuestionPost(Quiz formModel, int Question)
        {
            if (ModelState.IsValid)
            {
                var modelDb = QuizRepository.Find(formModel.ID);
                var modelQuestion = QuestionRepository.Find(Question);
                modelDb.Questions.Add(modelQuestion);
                if (this.TryUpdateModel(modelDb))
                {
                    QuizRepository.Update(modelDb);
                    QuizRepository.Save();

                    //return RedirectToAction("Index");
                }

            }
            FillDropdownValues();
            return View(formModel);
        }
        public ActionResult EditPost(Quiz formModel)
        {
            if (ModelState.IsValid)
            {
                var modelDb = QuizRepository.Find(formModel.ID);
                if(this.TryUpdateModel(modelDb))
                {
                    QuizRepository.Update(modelDb);
                    QuizRepository.Save();

                    return RedirectToAction("Index");
                }
            }

            FillDropdownValues();
            return View(formModel);
        }