public async Task <Category> UpdateCategory(int categoryId, Category category)
        {
            db.Entry(category).State = EntityState.Modified;
            await db.SaveChangesAsync();

            return(category);
        }
        public async Task <Product> UpdateProduct(int productId, Product product)
        {
            db.Entry(product).State = EntityState.Modified;
            await db.SaveChangesAsync();

            return(product);
        }