PDF Layout: Make pretix logo a layout element, not a background element

src/pretix/plugins/ticketoutputpdf/migrations/0003_auto_20180710_1321.py

@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+import json
+
+from django.db import migrations
+from django.db.models import Q
+
+
+def add_pretix_logo(app, schema_editor):
+    TicketLayout = app.get_model('ticketoutputpdf', 'TicketLayout')
+    for tl in TicketLayout.objects.filter(Q(background__isnull=True) | Q(background="")):
+        l = json.loads(tl.layout)
+        l.append({"type": "poweredby", "left": "88.72", "bottom": "10.00", "size": "20.00", "content": "dark"})
+        tl.layout = json.dumps(l)
+        tl.save(update_fields=['layout'])
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('ticketoutputpdf', '0002_auto_20180605_2022'),
+    ]
+
+    operations = [
+        migrations.RunPython(add_pretix_logo, migrations.RunPython.noop)
+    ]