public static int Create(User.User user, ProjectProduct product)
        {
            var expiryAt = DateTime.UtcNow.AddHours(product.duration_hours);

            return(ExecuteScalarInt(
                       @"INSERT INTO user_owned_products(guid, user_id, product_id, expiry_at, updated_at)
                                VALUES (@guid, @user_id, @product_id, @expiry_at, CURRENT_TIMESTAMP); 
                                SELECT currval('user_owned_products_id_seq');"
                       , new {
                guid = Guid.NewGuid().ToString(), user_id = user.id, product_id = product.id, expiry_at = expiryAt
            }
                       ));
        }
 public static int UsersCount(ProjectProduct product)
 => QueryInt(
     "SELECT COUNT(*) FROM user_owned_products WHERE product_id = @product_id", new {
     product_id = product.id
 }
     );