add firebase cli

lib/main-prod.dart

@@ -1,11 +1,17 @@
+import 'package:fcs/data/provider/messaging_fcm.dart';
+import 'package:firebase_core/firebase_core.dart';
+import 'package:firebase_messaging/firebase_messaging.dart';
 import 'package:flutter/material.dart';
 import 'package:logging/logging.dart';
 
 import 'app.dart';
 import 'config.dart';
 
-void main() {
+Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  await Firebase.initializeApp();
+  FirebaseMessaging.onBackgroundMessage(backgroundMessageHandler);
+
   Config(
       flavor: Flavor.PRODUCTION,
       color: Colors.blue,