Serialize the record to JSON. cls unused in this implementation.

        >>> s = teststore()
        >>> s.serialize('tstoretest', {'id': '1', 'name': 'Toto'})
        '{"id": "1", "name": "Toto"}'

def serialize(self, cls, record):
        """
        Serialize the record to JSON. cls unused in this implementation.

        >>> s = teststore()
        >>> s.serialize('tstoretest', {'id': '1', 'name': 'Toto'})
        '{"id": "1", "name": "Toto"}'
        """
        return json.dumps(record, cls=self.encoder)