public ActionResult New()
        {
            var categories = _context.Categories.ToList();
            var viewModel = new CategoriesForSingleQuestionViewModel()
            {
                Categories = categories,
                Question = new InterviewQuestion()

            };
            return View("QuestionForm",viewModel);
        }
        public ActionResult Edit(int id)
        {
            var question = _context.Questions.SingleOrDefault(q => q.Id == id);
            if (question == null)
                return HttpNotFound();

            var viewModel = new CategoriesForSingleQuestionViewModel
            {
                Categories = _context.Categories.ToList(),
                Question = question
            };

            return View("QuestionForm", viewModel);
        }
        public ActionResult Save(InterviewQuestion question)
        {
            if (!ModelState.IsValid)
            {
                var viewModel = new CategoriesForSingleQuestionViewModel
                {
                    Categories = _context.Categories.ToList(),
                    Question = question
                };
                return View("QuestionForm", viewModel);
            }
            if (question.Id == 0)
                _context.Questions.Add(question);
            else
            {
                var questionInDb = _context.Questions.Single(q => q.Id == question.Id);
                questionInDb.Question = question.Question;
                questionInDb.QuestionCategoryId = question.QuestionCategoryId;
            }
            _context.SaveChanges();

            return RedirectToAction("Index", "Question");
        }