Refactor: Inbox store, remove inboxes from sidebar (#387)

* Refactor: Inbox store, remove inboxes from sidebar

* Add a new page for inbox settings

* Show inboxes on sidebar

* Add inbox_members API

* Disable similar-code check

* Fix codeclimate scss issues

* Add widget_color update API and actions

* Add specs for inbox store

* Fix Facebook auth flow

* Fix agent loading, inbox name

app/javascript/dashboard/api/inboxMembers.js

@@ -0,0 +1,17 @@
+/* global axios */
+import ApiClient from './ApiClient';
+
+class InboxMembers extends ApiClient {
+  constructor() {
+    super('inbox_members');
+  }
+
+  create({ inboxId, agentList }) {
+    return axios.post(this.url, {
+      inbox_id: inboxId,
+      user_ids: agentList,
+    });
+  }
+}
+
+export default new InboxMembers();