title: Firebase & AngularFire2 'afAuth' does not exist on type 'Appcomponent'
body: <p>I'm currently trying to follow: <a href="https://github.com/angular/angularfire2" rel="nofollow noreferrer">https://github.com/angular/angularfire2</a></p>
  
  <p>I am getting an issue of:
      Property 'afAuth' does not exist on type 'AppComponent'.</p>
  
  <p>My app.component.ts looks like this:</p>
  
  <pre><code>import { Component } from '@angular/core';
  import { AngularFireDatabase, FirebaseListObservable } from 'angularfire2/database';
  import { AngularFireAuth } from 'angularfire2/auth';
  import { Observable } from "rxjs/Observable";
  import * as firebase from 'firebase/app';
  
  
  @Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
  })
  export class AppComponent {
    user: Observable&lt;firebase.User&gt;;
    items: FirebaseListObservable&lt;any[]&gt;;
    constructor(afAuth: AngularFireAuth, db: AngularFireDatabase) {
      this.user = afAuth.authState;
      this.items = db.list('items');
    }
    login() {
      this.afAuth.auth.signInWithPopup(new firebase.auth.GoogleAuthProvider());
    }
    logout() {
       this.afAuth.auth.signOut();
    }
  }
  </code></pre>
  
  <p>And my app.module.ts looks like this:</p>
  
  <pre><code>import { BrowserModule } from '@angular/platform-browser';
  import { NgModule } from '@angular/core';
  import { FormsModule } from '@angular/forms';
  import { HttpModule } from '@angular/http';
  import { AngularFireModule } from 'angularfire2';
  import { AngularFireDatabaseModule } from 'angularfire2/database';
  import { AngularFireAuthModule } from 'angularfire2/auth';
  import { AppComponent } from './app.component';
  import { environment } from '../environments/environment';
  
  export const firebaseConfig = {
      apiKey: 'xxxxxxxxxxxxxxxxxxxx',
      authDomain: 'xxxxxxxxxxxxx',
      databaseURL: 'xxxxxxxxxxxxxxxxxx',
      projectId: 'xxxxxxxxxxxxxxxxx',
      storageBucket: 'xxxxxxxxxxxxxxx',
      messagingSenderId: 'xxxxxxxxxx'
  };
  
  @NgModule({
    declarations: [
      AppComponent
    ],
    exports: [ AppComponent ],
    imports: [
      BrowserModule,
      FormsModule,
      HttpModule,
      AngularFireModule.initializeApp(firebaseConfig),
      AngularFireDatabaseModule,
      AngularFireAuthModule
    ],
    providers: [],
    bootstrap: [AppComponent]
  })
  export class AppModule { }
  </code></pre>
  
  <p>Anyone know how I would go about fixing this issue? (I am extremely new to programming - just wanting to throw data in to firebase but no tutorials seems to be showing me an up-to-date way on how to go about this)</p>