Merge pull request #81 from EnTeQuAk/feature/python-2.6

Fix python 2.6 compatibility

adminsortable/admin.py

@@ -101,7 +101,7 @@ class SortableAdmin(SortableAdminBase, ModelAdmin):
         order can be changed via drag-and-drop.
         """
         opts = self.model._meta
-        has_perm = request.user.has_perm('{}.{}'.format(opts.app_label,
+        has_perm = request.user.has_perm('{0}.{1}'.format(opts.app_label,
             opts.get_change_permission()))
 
         # get sort group index from querystring if present

adminsortable/models.py

@@ -51,7 +51,7 @@ class Sortable(models.Model):
                 sortable_foreign_keys.append(field)
         if len(sortable_foreign_keys) > 1:
             raise MultipleSortableForeignKeyException(
-                u'{} may only have one SortableForeignKey'.format(self))
+                u'{0} may only have one SortableForeignKey'.format(self))
 
     def save(self, *args, **kwargs):
         if not self.id: