check if a listing is still active

lib/services/storage/migrations/sql/2.active-flag-for-listings.js

@@ -0,0 +1,8 @@
+// Migration: there needs to be a unique index on job_id and hash as only
+// this makes the listing indeed unique
+
+export function up(db) {
+  db.exec(`
+    ALTER TABLE listings ADD COLUMN is_active INTEGER DEFAULT 1;
+  `);
+}