Create service for AccountBalances and use it.

src/accounts/accountBalances.service.ts

@@ -0,0 +1,18 @@
+// vim: set tw=80 ts=2 sw=2 sts=2 :
+import { Injectable } from '@angular/core';
+import { Observable } from 'rxjs/Rx';
+
+import { Restangular } from "ngx-restangular";
+
+import { AccountBalances } from './accountBalances';
+
+@Injectable()
+export class AccountBalancesService {
+  constructor(
+    private restangular: Restangular
+  ) {}
+
+  get(id: number): Observable<AccountBalances> {
+    return this.restangular.one('account', id).one('balances').get();
+  }
+}