Create a new :class:`UserStory`.

        :param project: :class:`Project` id
        :param subject: subject of the :class:`UserStory`
        :param attrs: optional attributes of the :class:`UserStory`

def create(self, project, subject, **attrs):
        """
        Create a new :class:`UserStory`.

        :param project: :class:`Project` id
        :param subject: subject of the :class:`UserStory`
        :param attrs: optional attributes of the :class:`UserStory`
        """
        attrs.update({'project': project, 'subject': subject})
        return self._new_resource(payload=attrs)