title: AngularFIRE Property 'subscribe' does not exist on type 'AngularFireList<{}>'
body: <p>I'm following <a href="https://www.youtube.com/watch?v=mqWXRX5fxGQ" rel="noreferrer"><strong>this tutorial</strong></a> about how to connect angular with firebase database. But in minute 17:30 I'm getting this error:</p>
  
  <p><strong>Property 'subscribe' does not exist  on type 'AngularFireList&lt;{}>'</strong></p>
  
  <p>my AppComponent:</p>
  
  <pre><code>import { Component } from '@angular/core';
  import {AngularFireDatabase, AngularFireDatabaseModule} from 'angularfire2/database';
  
  import {AngularFireAuth, AngularFireAuthModule} from 'angularfire2/auth';
  import { Observable } from 'rxjs/Observable';
  import * as firebase from 'firebase/app';
  import { Country } from './models/country';
  
  @Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
  })
  
  export class AppComponent {
    countries: any[];
  
    constructor(db: AngularFireDatabase )
    {
       db.list('/Country/countries')
       .subscribe(countries =&gt; { //  &lt;--ERROR IS HERE
        this.countries = countries;
        console.log(this.countries);
        });
    }
  }
  </code></pre>
  
  <p>My model:</p>
  
  <pre><code>export class Country {
       // --ATTRIB--
       id: string;
       name: string;
       code: string;
       urlFlag: string;
  }
  </code></pre>
  
  <p>Cant find anything about this error. I'm beginner in angular. Thanks if can help me.</p>