Add Dexie for persistence; user management with dexie; this is the way

web/src/app/db.js

@@ -0,0 +1,15 @@
+import Dexie from 'dexie';
+
+// Uses Dexie.js
+// https://dexie.org/docs/API-Reference#quick-reference
+//
+// Notes:
+// - As per docs, we only declare the indexable columns, not all columns
+
+const db = new Dexie('ntfy');
+
+db.version(1).stores({
+    users: '&baseUrl, username',
+});
+
+export default db;