title: Pass boolean from observable to observable
body: <p>I want to check in my adminauthguard if the user has set a adminflag(in Firebase using angularfire2)</p>
  
  <pre><code>canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot):Observable&lt;boolean&gt; | boolean {
      return this.loginservice.af.auth.map((auth) =&gt;  {
        if(auth == null) {
          return false;
        } else {
          this.membersservice.get(auth.uid).subscribe(users =&gt; {
            if(users.admin == true) {
              return true;
            } else {
              return false;
            }
          })
        }
      });
  </code></pre>
  
  <p>how can I resolve the observable in the observable inside?</p>