Convert our JSON object to a string before we save

def get_db_prep_save(self, value, connection, **kwargs):
        """Convert our JSON object to a string before we save"""
        if value is None and self.null:
            return None
        # default values come in as strings; only non-strings should be
        # run through `dumps`
        if not isinstance(value, six.string_types):
            value = dumps(value)

        return value