add pgmq migration test script

Author: olirice

nix/tests/migrations/pgmq.sql

@@ -0,0 +1,12 @@
+select
+  pgmq.create('Foo');
+
+select
+  *
+from
+  pgmq.send(
+    queue_name:='Foo',
+    msg:='{"foo": "bar1"}'
+  );
+
+