change db from localhost to xos_db

Change-Id: If3c5fe069c3d861ed0bc81fb047fe31ddfd74770
diff --git a/xos/synchronizer/onos_synchronizer_config b/xos/synchronizer/onos_synchronizer_config
index c6ceece..c7a2f2c 100644
--- a/xos/synchronizer/onos_synchronizer_config
+++ b/xos/synchronizer/onos_synchronizer_config
@@ -7,7 +7,7 @@
 name=xos
 user=postgres
 password=password
-host=localhost
+host=xos_db
 port=5432
 
 [api]