public IActionResult Create(BooksCreateVM booksCreateVM)
        {
            if (ModelState.IsValid)
            {
                _appDbContext.Books.Add(booksCreateVM.Books);
                _appDbContext.SaveChanges();

                return(RedirectToAction("Index"));
            }
            return(View(booksCreateVM));
        }
        public IActionResult Edit(int?id)
        {
            BooksCreateVM booksVM = new BooksCreateVM()
            {
                Books = _appDbContext.Books.Find(id),
                CategorySelectList = _appDbContext.Categories.Select(item => new SelectListItem
                {
                    Text  = item.CategoryName,
                    Value = item.Id.ToString()
                })
            };

            return(View(booksVM));
        }