diff --git a/schema/20181210.sql b/schema/20181210.sql
index 05236ca..e6be91d 100644
--- a/schema/20181210.sql
+++ b/schema/20181210.sql
@@ -83,7 +83,8 @@ CREATE TABLE public.notifications (
     states integer[] NOT NULL,
     output text,
     inserted timestamp with time zone DEFAULT now() NOT NULL,
-    sent timestamp with time zone
+    sent timestamp with time zone,
+    mapping_id integer not null references mappings(id),
 );