public IActionResult RemoveProduct(int productId)
        {
            var product = _repository.GetProductById(productId);

            if (product == null)
            {
                return(NotFound("Cannot find the specified product."));
            }

            _repository.RemoveEntity(product);

            if (_repository.SaveChanges())
            {
                return(RedirectToAction("AdminPage", "AdminPage"));
            }

            return(BadRequest("Cannot save the changes to the database."));
        }