Update base.py
StaffelnPersistentObject inherited from ovoo_base.VersionedObject
diff --git a/staffeln/objects/base.py b/staffeln/objects/base.py
index ea04b59..dd0730d 100755
--- a/staffeln/objects/base.py
+++ b/staffeln/objects/base.py
@@ -40,7 +40,7 @@
OBJ_BASE_CLASS = StaffelnObject
-class StaffelnPersistentObject(object):
+class StaffelnPersistentObject(ovoo_base.VersionedObject):
fields = {
"created_at": ovoo_fields.DateTimeField(nullable=True),
# "deleted_at": ovoo_fields.DateTimeField(nullable=True),