Add a containerfile

lib/components/menubar.dart

@@ -1,16 +1,17 @@
+// This project is not supposed to be cross-platform, 
+// so we don't care about this warning
+// ignore: avoid_web_libraries_in_flutter
 import 'dart:html';
 
 import 'package:flutter/material.dart';
 import 'package:softplayer_web/components/sign_in_form.dart';
 
-/// Flutter code sample for [AppBar].
-
 class MenuPanel extends StatefulWidget implements PreferredSizeWidget {
   final TabName tab;
   const MenuPanel({super.key, required this.tab})
       : preferredSize = const Size.fromHeight(kToolbarHeight);
   @override
-  final Size preferredSize; // default is 56.0
+  final Size preferredSize;
   @override
   State<StatefulWidget> createState() => _MenuPanel();
 }
@@ -21,6 +22,7 @@ class _MenuPanel extends State<MenuPanel> {
   bool isSignedIn() {
     return window.localStorage.containsKey("token");
   }
+
   List<Widget> accountActions() {
     if (isSignedIn()) {
       return [
@@ -37,7 +39,8 @@ class _MenuPanel extends State<MenuPanel> {
                   builder: (BuildContext context) => const SignInForm());
             },
             child: const Text("sign in")),
-        TextButton(onPressed: () => print("sign up"), child: const Text("sign up")),
+        TextButton(
+            onPressed: () => print("sign up"), child: const Text("sign up")),
       ];
     }
   }