Add notification trigger function to DB

etc/db/database-template.sql

@@ -144,6 +144,31 @@ CREATE EXTENSION IF NOT EXISTS postgis_topology WITH SCHEMA topology;
 COMMENT ON EXTENSION postgis_topology IS 'PostGIS topology spatial types and functions';
 
 
+--
+-- Name: notify(); Type: FUNCTION; Schema: public; Owner: postgres
+--
+
+CREATE FUNCTION public.notify() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+DECLARE
+channel text := TG_ARGV[0];
+BEGIN
+PERFORM pg_notify(channel, json_build_object(
+'tstamp', CURRENT_TIMESTAMP,
+'operation', TG_OP,
+'schema', TG_TABLE_SCHEMA,
+'table', TG_TABLE_NAME,
+'old', row_to_json(OLD),
+'new', row_to_json(NEW)
+)::text);
+RETURN NULL;
+END;
+$$;
+
+
+ALTER FUNCTION public.notify() OWNER TO postgres;
+
 --
 -- Name: set_survey(text); Type: PROCEDURE; Schema: public; Owner: postgres
 --