Allow overriding topic

core/migrations/0015_notificationrule_topic.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.1.5 on 2023-01-12 18:14
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0014_notificationrule_priority'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='notificationrule',
+            name='topic',
+            field=models.CharField(blank=True, max_length=255, null=True),
+        ),
+    ]