public ActionResult Index()
        {
            var index = 0;
            var model = new CatalogViewModel();

            model.AddProduct(new Product {
                Id = ++index, Name = "Galaxy S10"
            });
            model.AddProduct(new Product {
                Id = ++index, Name = "Google Pixel 3"
            });
            model.AddProduct(new Product {
                Id = ++index, Name = "Galaxy Note 9"
            });
            model.AddProduct(new Product {
                Id = ++index, Name = "OnePlus 7"
            });

            return(View("~/Views/Feature/Products/Catalog.cshtml", model));
        }