'stamp' not created in workflow_node table in postgres

This applies to 5.x-1.2 as well.
Although stamp has been added to the workflow_node table for mysql in the _install function the table definition has not changed for postgres

I believe the following change to workflow.install solves the problem

========================
@@ -186,6 +186,7 @@
nid SERIAL,
sid integer NOT NULL default '0',
uid integer NOT NULL default '0',
+ stamp integer,
PRIMARY KEY (nid)
);
QUERY
========================

Thanks,
Steven