Added try-except block into page lock permission migrations

wagtail/wagtailcore/migrations/0005_add_page_lock_permission_to_moderators.py

@@ -10,11 +10,16 @@ def add_page_lock_permission_to_moderators(apps, schema_editor):
     GroupPagePermission = apps.get_model('wagtailcore.GroupPagePermission')
 
     root_pages = Page.objects.filter(depth=1)
-    moderators_group = Group.objects.get(name='Moderators')
 
-    for page in root_pages:
-        GroupPagePermission.objects.create(
-            group=moderators_group, page=page, permission_type='lock')
+    try:
+        moderators_group = Group.objects.get(name='Moderators')
+
+        for page in root_pages:
+            GroupPagePermission.objects.create(
+                group=moderators_group, page=page, permission_type='lock')
+
+    except Group.DoesNotExist:
+        pass
 
 
 class Migration(migrations.Migration):

wagtail/wagtailcore/south_migrations/0008_add_page_lock_permission_to_moderators.py

@@ -15,11 +15,17 @@ class Migration(DataMigration):
             set_autocommit(True)    
 
         root_pages = orm['wagtailcore.page'].objects.filter(depth=1)
-        moderators_group = orm['auth.group'].objects.get(name='Moderators')
 
-        for page in root_pages:
-            orm['wagtailcore.grouppagepermission'].objects.create(
-                group=moderators_group, page=page, permission_type='lock')
+
+        try:
+            moderators_group = orm['auth.group'].objects.get(name='Moderators')
+
+            for page in root_pages:
+                orm['wagtailcore.grouppagepermission'].objects.create(
+                    group=moderators_group, page=page, permission_type='lock')
+
+        except orm['auth.group'].DoesNotExist:
+            pass
 
     def backwards(self, orm):
         pass