Publish a message to the queue.

        :param str message: The message to send

def publish(self, message):
        """
        Publish a message to the queue.

        :param str message: The message to send
        """
        props = pika.BasicProperties(content_type='text/plain', delivery_mode=1)
        self.channel.basic_publish(self._exchange,
                                   self._routing_key,
                                   message,
                                   props)