add class flag

electron/controller/example.js

@@ -630,4 +630,5 @@ class ExampleController extends Controller {
   }   
 }
 
+ExampleController.toString = () => '[class ExampleController]';
 module.exports = ExampleController;

electron/service/example.js

@@ -25,4 +25,5 @@ class ExampleService extends Service {
   }
 }
 
+ExampleService.toString = () => '[class ExampleService]';
 module.exports = ExampleService;

electron/service/storage.js

@@ -228,4 +228,5 @@ class StorageService extends Service {
   }  
 }
 
+StorageService.toString = () => '[class StorageService]';
 module.exports = StorageService;