public async Task <ActionResult> Create([Bind(Include = "ProductId,ItemId")] ProductItem productItem)
        {
            if (ModelState.IsValid)
            {
                var canCreate = await productItem.CanCreate(db);

                if (canCreate)
                {
                    db.ProductItems.Add(productItem);
                    await db.SaveChangesAsync();

                    return(RedirectToAction("Index"));
                }
                ModelState.AddModelError("", "Info already created!");
            }
            var model = await productItem.Convert(db);

            return(View(model));
        }