db: add migration to set subscriptions.status not null

Author: alexsavio

migrations/20240403111607_make_status_not_null_in_subscriptions.sql

@@ -0,0 +1,5 @@
+-- Add migration script here
+BEGIN;
+    UPDATE subscriptions SET status = 'confirmed' WHERE status IS NULL;
+    ALTER TABLE subscriptions ALTER COLUMN status SET NOT NULL;
+COMMIT;