Missing imports and environment var for hub

src/app/hub.service.ts

@@ -1,5 +1,7 @@
 import {Injectable} from '@angular/core';
 import {HttpClient} from '@angular/common/http';
+import {Observable} from 'rxjs';
+import {environment} from '../environments/environment';
 
 @Injectable({
   providedIn: 'root'

src/environments/environment.ts

@@ -7,6 +7,7 @@ export const environment = {
   hostname: 'localhost:4201',
   nodeHostname: 'node.deso.org',  // TODO deleteme
   walletSyncHostname: 'localhost:8091',
+  hubHostname: '', // TODO put me in a config file, or make this whole file a config file
 };
 
 /*