Make it so that scoped model can run on web

Author: brianegan

scoped_model/lib/main.dart

@@ -1,17 +1,23 @@
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:path_provider/path_provider.dart';
 import 'package:scoped_model_sample/app.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 import 'package:todos_repository_local_storage/todos_repository_local_storage.dart';
 
-void main() {
+void main() async {
   WidgetsFlutterBinding.ensureInitialized();
 
-  var todoRepo = const LocalStorageRepository(
-    localStorage: FileStorage(
-      'scoped_model_todos',
-      getApplicationDocumentsDirectory,
+  final localStorage = kIsWeb
+      ? KeyValueStorage(
+          'scoped_model_todos',
+          await SharedPreferences.getInstance(),
+        )
+      : FileStorage('scoped_model_todos', getApplicationDocumentsDirectory);
+
+  runApp(
+    ScopedModelApp(
+      repository: LocalStorageRepository(localStorage: localStorage),
     ),
   );
-
-  runApp(ScopedModelApp(repository: todoRepo));
 }