Configurable invoice prefixes

src/pretix/base/migrations/0069_invoice_prefix.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.2 on 2017-07-17 19:29
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+from django.db.models import deletion
+
+
+def fwd(app, schema_editor):
+    Event = app.get_model('pretixbase', 'Event')
+    for e in Event.objects.select_related('organizer').all():
+        e.invoices.all().update(prefix=e.slug.upper() + '-', organizer=e.organizer)
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('pretixbase', '0068_subevent_frontpage_text'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='invoice',
+            name='prefix',
+            field=models.CharField(db_index=True, default='', max_length=160),
+            preserve_default=False,
+        ),
+        migrations.AddField(
+            model_name='invoice',
+            name='organizer',
+            field=models.ForeignKey(null=True,
+                                    on_delete=deletion.PROTECT,
+                                    related_name='invoices', to='pretixbase.Organizer'),
+            preserve_default=False,
+        ),
+        migrations.RunPython(
+            fwd, migrations.RunPython.noop
+        ),
+        migrations.AlterUniqueTogether(
+            name='invoice',
+            unique_together=set([('organizer', 'prefix', 'invoice_no')]),
+        ),
+        migrations.AlterField(
+            model_name='invoice',
+            name='organizer',
+            field=models.ForeignKey(on_delete=deletion.PROTECT, related_name='invoices', to='pretixbase.Organizer'),
+        ),
+    ]