Create the index schema

        Parameters
        ----------
        hash_key : :class:`~.DynamoKey`
            The hash key of the table

def schema(self, hash_key):
        """
        Create the index schema

        Parameters
        ----------
        hash_key : :class:`~.DynamoKey`
            The hash key of the table

        """
        key_schema = [hash_key.hash_schema()]
        if self.range_key is not None:
            key_schema.append(self.range_key.range_schema())
        schema_data = {
            'IndexName': self.name,
            'KeySchema': key_schema,
            'Projection': {
                'ProjectionType': self.projection_type,
            }
        }
        if self.include_fields is not None:
            schema_data['Projection']['NonKeyAttributes'] = self.include_fields
        return schema_data