Added database migration

RIGS/migrations/0024_auto_20160229_2042.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('RIGS', '0023_auto_20150529_0048'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='event',
+            name='based_on',
+            field=models.ForeignKey(related_name='future_events', on_delete=django.db.models.deletion.SET_NULL, blank=True, to='RIGS.Event', null=True),
+        ),
+    ]