public function queue($time_to_send = 'now')
    {
        if($time_to_send == 'now') {
            $time_to_send = time();
        }

        $item = new Queue();

        $item->subject = $this->getSubject();
        $item->attempts = 0;
        $item->swift_message = base64_encode(serialize($this));
        $item->time_to_send = date('Y-m-d H:i:s', $time_to_send);

        return $item->save();
    }