added migration for extra social feed option (facebook)

wagtailsocialfeed/migrations/0003_auto_20161006_1021.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.2 on 2016-10-06 08:21
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('wagtailsocialfeed', '0002_auto_20161005_1032'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='socialfeedconfiguration',
+            name='source',
+            field=models.CharField(choices=[('twitter', 'Twitter'), ('instagram', 'Instagram'), ('facebook', 'Facebook')], max_length=100, verbose_name='Feed source'),
+        ),
+    ]