Extend department membership to groups by default

The setting is useful in making sure the staff members with access to the
department can get alerts and available as possible assignees.

include/i18n/en_US/department.yaml

@@ -17,6 +17,7 @@
   signature: |
     Support Department
   ispublic: 1
+  group_membership: 1
 
 - id: 2
   name: Sales
@@ -24,9 +25,11 @@
     Sales and Customer Retention
   ispublic: 1
   sla_id: 1
+  group_membership: 1
 
 - id: 3
   name: Maintenance
   signature: |
     Maintenance Department
   ispublic: 0
+  group_membership: 0

include/staff/department.inc.php

@@ -19,6 +19,9 @@ if($dept && $_REQUEST['a']!='add') {
     $info['ispublic']=isset($info['ispublic'])?$info['ispublic']:1;
     $info['ticket_auto_response']=isset($info['ticket_auto_response'])?$info['ticket_auto_response']:1;
     $info['message_auto_response']=isset($info['message_auto_response'])?$info['message_auto_response']:1;
+    if (!isset($info['group_membership']))
+        $info['group_membership'] = 1;
+
     $qstr.='&a='.$_REQUEST['a'];
 }
 $info=Format::htmlchars(($errors && $_POST)?$_POST:$info);