use custom user and permission model

core/authentication/migrations/0004_legacy_user.py

@@ -0,0 +1,19 @@
+from django.conf import settings
+from django.db import migrations
+
+from authentication.models import ExtendedUser
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('authentication', '0003_groups'),
+    ]
+
+    def create_legacy_user(apps, schema_editor):
+        ExtendedUser.objects.create_user(settings.LEGACY_USER_NAME, 'mail@' + settings.MAIL_DOMAIN,
+                                         settings.LEGACY_USER_PASSWORD)
+
+    operations = [
+        migrations.RunPython(create_legacy_user)
+    ]