Sendmail: Allow to disable rules (#2111)

src/pretix/plugins/sendmail/migrations/0002_rule_enabled.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.3 on 2021-06-07 09:00
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sendmail', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='rule',
+            name='enabled',
+            field=models.BooleanField(default=True),
+        ),
+    ]