[databases] Add missing ordering requirements for back-ups

beat/web/databases/migrations/0003_auto_20160630_1710.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.5 on 2016-06-30 17:10
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('databases', '0002_scheduler_addons'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='database',
+            options={'ordering': ['previous_version_id', 'fork_of_id', 'id']},
+        ),
+    ]