public ActionResult Create()
        {
            var viewmodel = new ShopProductCreateModel();
            viewmodel.SetCategory();

            return View(viewmodel);
        }
        public ActionResult Create(ShopProductCreateModel viewmodel)
        {
            if (ModelState.IsValid) {
                _service.Create(viewmodel.Product);

                return RedirectToAction("Index");
            }

            return View(viewmodel);
        }