Another change to previous revision.

sql/database-create.sql

@@ -322,6 +322,7 @@ CREATE TABLE `apt_instances` (
   `privkey` mediumtext,
   `repourl` tinytext,
   `reponame` varchar(40) default NULL,
+  `reporef` varchar(128) default NULL,
   `repohash` varchar(64) default NULL,
   `rspec` mediumtext,
   `script` mediumtext,

sql/updates/4/551

@@ -32,7 +32,8 @@ sub DoUpdate($$$)
         DBQueryFatal("alter table apt_instances " .
 		     " add `repourl` tinytext after privkey, ".
 		     " add `reponame` varchar(40) default NULL after repourl, ".
-		     " add `repohash` varchar(64) default NULL after reponame");
+		     " add `reporef` varchar(128) default NULL after reponame,".
+		     " add `repohash` varchar(64) default NULL after reporef");
     }
     if (!DBSlotExists("apt_instance_history", "repourl")) {
         DBQueryFatal("alter table apt_instance_history " .