Deal with cancelling memberships (#2130)

src/pretix/base/migrations/0194_membership_canceled.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.3 on 2021-06-17 10:28
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0193_auto_20210611_1355'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='membership',
+            name='canceled',
+            field=models.BooleanField(default=False),
+        ),
+    ]