Add explicit extension column to voip_pbx_groups.

db_scripts/diff/15005.up

@@ -19,6 +19,7 @@ CREATE TABLE `voip_pbx_groups` (
   `contract_id` int(11) unsigned NOT NULL,
   `number_id` int(11) unsigned DEFAULT NULL,
   `name` varchar(255) NOT NULL,
+  `extension` varchar(255) DEFAULT NULL,
   `hunt_policy` enum('serial','parallel') NOT NULL DEFAULT 'serial',
   `hunt_policy_timeout` int(4) unsigned NOT NULL,
   PRIMARY KEY (`id`),