Add a user field specifically for XMPP, because it needs to be handled a little differently to the user profiles (different mf2 property, stuff like that)

users/migrations/0009_user_xmpp.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.7 on 2017-11-06 10:59
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0008_auto_20171031_1357'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='user',
+            name='xmpp',
+            field=models.EmailField(blank=True, max_length=254),
+        ),
+    ]