Adds an item to the queue.

        Generates a uid for later referral.
        Enqueues the uid and stores the item.

def put(self, item):
        """Adds an item to the queue.

        Generates a uid for later referral.
        Enqueues the uid and stores the item.
        """
        uid = str(uuid.uuid4())

        if self.serializer is not None:
            item = self.serializer.dumps(item)

        self._redis.pipeline()\
                .hset(self.ITEMS_KEY, uid, item)\
                .lpush(self.QUEUE_KEY, uid)\
                .execute()
        return uid