Update sync_controller_slices.py
fixes #50
diff --git a/xos/openstack_observer/steps/sync_controller_slices.py b/xos/openstack_observer/steps/sync_controller_slices.py
index df44fa5..619a6ed 100644
--- a/xos/openstack_observer/steps/sync_controller_slices.py
+++ b/xos/openstack_observer/steps/sync_controller_slices.py
@@ -5,6 +5,7 @@
from django.db.models import F, Q
from xos.config import Config
from observer.openstacksyncstep import OpenStackSyncStep
+from core.models import User
from core.models.slice import Slice, ControllerSlice
from core.models.controlleruser import ControllerUser
from util.logger import Logger, logging, logger