title: consume Services from core module in app.component
body: <p>Hi im new at angular 2 and Im trying to put in place all the things I have learned in angular.io.
  The problem is that I have readed about the core module, services, injectables ... and</p>
  
  <p>If I have lets say a core-module like this: </p>
  
  <pre><code>import { NgModule } from '@angular/core';
  import { LoggerService } from './services/logger.service';
  
  @NgModule({
      exports: [
          //components
          LoggerComponent,
      ],
      declarations: [LoggerComponent],
      providers: [LoggerService],
  })
  export class CoreModule { }
  </code></pre>
  
  <p>and a simple app.module like:</p>
  
  <pre><code>import { CoreModule } from './core/core.module';
  import { AppComponent } from './app.component';
  
  @NgModule({
      imports: [
          CoreModule,
          BrowserModule,
          HttpModule,
          routerModule,
      ],
      declarations: [
          AppComponent,
      ],
      providers: [],
      bootstrap: [AppComponent],
  })
  export class AppModule { }
  </code></pre>
  
  <p>How can I use the LoggerService service exported for the core-module? i have to</p>
  
  <pre><code>import {LoggerService} from './core/services';
  </code></pre>
  
  <p>in my app.component? because in the contructor of app.component its not working </p>
  
  <pre><code>constructor(logger: LoggerService){}
  </code></pre>
  
  <p>what Im missing? thanks!</p>