Set the current site ID, and ``is_public`` based on the setting
        ``COMMENTS_DEFAULT_APPROVED``.

def save(self, *args, **kwargs):
        """
        Set the current site ID, and ``is_public`` based on the setting
        ``COMMENTS_DEFAULT_APPROVED``.
        """
        if not self.id:
            self.is_public = settings.COMMENTS_DEFAULT_APPROVED
            self.site_id = current_site_id()
        super(ThreadedComment, self).save(*args, **kwargs)