public ActionResult Create(CategoryViewModel form)
 {
     if (ModelState.IsValid)
     {
         var category = new Category();
         category.CategoryName = form.CategoryName;
         category.Description = form.Description;
         _context.Categories.Add(category);
         _context.SaveChanges();
         return RedirectToAction("Index").WithSuccess("Category created.");
     }
     return View(form);
 }
        public ActionResult Edit(CategoryViewModel form)
        {
            if (ModelState.IsValid)
            {
                var model = _context.Categories.SingleOrDefault(i => i.CategoryID == form.CategoryID);

                model.CategoryName = form.CategoryName;
                model.Description = form.Description;
                _context.Entry(model).State = EntityState.Modified;
                _context.SaveChanges();
                return RedirectToAction("Index").WithSuccess("Category saved.");
            }
            return View(form);
        }