Set the site to the current site when the record is first
        created, or the ``update_site`` argument is explicitly set
        to ``True``.

def save(self, update_site=False, *args, **kwargs):
        """
        Set the site to the current site when the record is first
        created, or the ``update_site`` argument is explicitly set
        to ``True``.
        """
        if update_site or (self.id is None and self.site_id is None):
            self.site_id = current_site_id()
        super(SiteRelated, self).save(*args, **kwargs)