Filter the change list by currently logged in user if not a
        superuser. We also skip filtering if the model for this admin
        class has been added to the sequence in the setting
        ``OWNABLE_MODELS_ALL_EDITABLE``, which contains models in the
        format ``app_label.object_name``, and allows models subclassing
        ``Ownable`` to be excluded from filtering, eg: ownership should
        not imply permission to edit.

def get_queryset(self, request):
        """
        Filter the change list by currently logged in user if not a
        superuser. We also skip filtering if the model for this admin
        class has been added to the sequence in the setting
        ``OWNABLE_MODELS_ALL_EDITABLE``, which contains models in the
        format ``app_label.object_name``, and allows models subclassing
        ``Ownable`` to be excluded from filtering, eg: ownership should
        not imply permission to edit.
        """
        opts = self.model._meta
        model_name = ("%s.%s" % (opts.app_label, opts.object_name)).lower()
        models_all_editable = settings.OWNABLE_MODELS_ALL_EDITABLE
        models_all_editable = [m.lower() for m in models_all_editable]
        qs = super(OwnableAdmin, self).get_queryset(request)
        if request.user.is_superuser or model_name in models_all_editable:
            return qs
        return qs.filter(user__id=request.user.id)