Send automatic payment reminder emails, redesign mail settings

src/pretix/base/migrations/0036_auto_20160902_0755.py

@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.4 on 2016-09-02 07:55
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+def preserve_event_settings(apps, schema_editor):
+    Event = apps.get_model('pretixbase', 'Event')
+    EventSetting = apps.get_model('pretixbase', 'EventSetting')
+    for e in Event.objects.all():
+        EventSetting.objects.create(object=e, key='mail_days_order_expire_warning', value='0')
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0035_merge'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='order',
+            name='expiry_reminder_sent',
+            field=models.BooleanField(default=False),
+        ),
+        migrations.AlterField(
+            model_name='item',
+            name='allow_cancel',
+            field=models.BooleanField(default=True, help_text='If you deactivate this, an order including this product might not be cancelled by the user. It may still be cancelled by you.', verbose_name='Allow product to be cancelled'),
+        ),
+        migrations.RunPython(preserve_event_settings)
+    ]