[Fix] forgetten NgModule syntax

Author: sqlProvider

src/angular2-pubsub.module.ts

@@ -1,6 +1,7 @@
 import { PubSubService } from './angular2-pubsub.service';
 import { ModuleWithProviders, NgModule } from '@angular/core';
 
+@NgModule()
 export class PubSubModule {
   public static forRoot(): ModuleWithProviders {
     return {