Checks for user

src/app/navbar/navbar.component.ts

@@ -39,7 +39,11 @@ export class NavbarComponent {
     if (isSignedIn()) {
       this.api.getUser().subscribe(u => {
         this.user = u;
+
+        if (this.user && this.user.uid) {
           this.googleAnalyticsService.setUser(this.user.uid);
+        }
+
         this._loadNavLinks();
       }, error => {
         localStorage.removeItem('token');