public async Task <ActionResult <Wishlist> > AddItemToWishlist(Book book)
        {
            var wishlist = await _repository.AddBookToWishlistAsync(book);

            return(CreatedAtAction("GetWishlistItemById", new { id = wishlist.Id }, wishlist));
        }
        public async Task <ActionResult <Wishlist> > AddItemToWishlist(Book book)
        {
            var wishlist = await _repository.AddBookToWishlistAsync(book);

            return(Ok(wishlist));
        }