Ensure unicity on actor username and domain

api/funkwhale_api/federation/migrations/0002_auto_20180403_1620.py

+# Generated by Django 2.0.3 on 2018-04-03 16:20
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('federation', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name='actor',
+            unique_together={('domain', 'preferred_username')},
+        ),
+    ]

api/funkwhale_api/federation/models.py

@@ -32,6 +32,9 @@ class Actor(models.Model):
         default=timezone.now)
     manually_approves_followers = models.NullBooleanField(default=None)
 
+    class Meta:
+        unique_together = ['domain', 'preferred_username']
+
     @property
     def webfinger_subject(self):
         return '{}@{}'.format(