CORD-1244 Modify model_policies for OpenStack synchronizer

Change-Id: I8e946e3ca665689bd0449b80d87fe4bb29afde99
diff --git a/xos/synchronizer/model_policies/model_policy_Site.py b/xos/synchronizer/model_policies/model_policy_Site.py
index 07fe6f3..e0e288d 100644
--- a/xos/synchronizer/model_policies/model_policy_Site.py
+++ b/xos/synchronizer/model_policies/model_policy_Site.py
@@ -1,14 +1,22 @@
 from synchronizers.new_base.modelaccessor import *
+from synchronizers.new_base.policy import Policy
 
-def handle(site):
-    # site = Site.get(site_id)
-    # make sure site has a ControllerSite record for each controller
-    ctrl_sites = ControllerSite.objects.filter(site_id=site.id)
-    existing_controllers = [cs.controller for cs in ctrl_sites]
-    existing_controller_ids = [c.id for c in existing_controllers]
+class SitePolicy(Policy):
+    model_name = "Site"
 
-    all_controllers = Controller.objects.all()
-    for ctrl in all_controllers:
-        if ctrl.id not in existing_controller_ids:
-            ctrl_site = ControllerSite(controller=ctrl, site=site)
-            ctrl_site.save() 
+    def handle_create(self, site):
+        return self.handle_update(site)
+
+    def handle_update(self, site):
+        # site = Site.get(site_id)
+        # make sure site has a ControllerSite record for each controller
+        ctrl_sites = ControllerSite.objects.filter(site_id=site.id)
+        existing_controllers = [cs.controller for cs in ctrl_sites]
+        existing_controller_ids = [c.id for c in existing_controllers]
+
+        all_controllers = Controller.objects.all()
+        for ctrl in all_controllers:
+            if ctrl.id not in existing_controller_ids:
+                ctrl_site = ControllerSite(controller=ctrl, site=site)
+                ctrl_site.save()
+