public function scopeWhereUser($query, $userId)
    {
        return $query->join(
                Config::get('shop.order_table'),
                Config::get('shop.order_table') . '.id',
                '=',
                Config::get('shop.transaction_table') . '.order_id'
            )
            ->where(Config::get('shop.order_table') . '.user_id', $userId);
    }