title: Is it possible to use angularfire2 with Angular 6?
body: <p>I'm trying to add firebase support to my Angular 6 app but when adding angularfire2 </p>
  
  <pre><code>npm install angularfire2 firebase
  </code></pre>
  
  <p>I get a lot of warning saying I must use Angular 5. For example</p>
  
  <pre><code>npm WARN angularfire2@5.0.0-rc.6.0 requires a peer of @angular/core@^5.0.0 but none is installed. You must install peer dependencies yourself.
  </code></pre>
  
  <p>Is it possible to use angularfire2 with Angular 6 today?</p>
  
  <p>I get this error when compiling:</p>
  
  <pre><code>ERROR in node_modules/angularfire2/angularfire2.d.ts(3,10): error TS2305: Module '"/home/rrr/Projects/ng6test/node_modules/rxjs/Subscription"' has no exported member 'Subscription'.
  node_modules/angularfire2/firebase.app.module.d.ts(10,22): error TS2720: Class 'FirebaseApp' incorrectly implements class 'FirebaseApp'. Did you mean to extend 'FirebaseApp' and inherit its members as a subclass?
    Property 'automaticDataCollectionEnabled' is missing in type 'FirebaseApp'.
  node_modules/rxjs/Subscription.d.ts(1,15): error TS2307: Cannot find module 'rxjs-compat/Subscription'.
  </code></pre>
  
  <p>I tried to install rxjs-compat but after that I get another warning</p>
  
  <pre><code>ERROR in node_modules/angularfire2/firebase.app.module.d.ts(10,22): error TS2720: Class 'FirebaseApp' incorrectly implements class 'FirebaseApp'. Did you mean to extend 'FirebaseApp' and inherit its members as a subclass?
    Property 'automaticDataCollectionEnabled' is missing in type 'FirebaseApp'.
  </code></pre>