change db from localhost to xos_db

Change-Id: Ic1db87b3b0153f905d6d00ae2a72ce2c74a720ac
diff --git a/xos/synchronizer/vtn_synchronizer_config b/xos/synchronizer/vtn_synchronizer_config
index 9c99456..dad5cb6 100644
--- a/xos/synchronizer/vtn_synchronizer_config
+++ b/xos/synchronizer/vtn_synchronizer_config
@@ -7,7 +7,7 @@
 name=xos
 user=postgres
 password=password
-host=localhost
+host=xos_db
 port=5432
 
 [api]