Add index element route

app/router.js

@@ -7,7 +7,7 @@ export default class Router extends EmberRouter {
 }
 
 Router.map(function () {
-  this.route('indexes', function() {
+  this.route('indexes', function () {
     this.route('element', { path: '/:index_id' });
   });
 });

app/routes/indexes.js

@@ -1,7 +1,10 @@
 import Route from '@ember/routing/route';
+import { inject as service } from '@ember/service';
 
 export default class IndexesRoute extends Route {
-  model() {
+  @service store;
+
+  async model() {
     return this.store.findAll('index');
   }
 }

app/routes/indexes/element.js

@@ -1,4 +1,10 @@
 import Route from '@ember/routing/route';
+import { inject as service } from '@ember/service';
 
 export default class IndexesElementRoute extends Route {
+  @service store;
+
+  async model({ index_id }) {
+    return this.store.find('index', index_id);
+  }
 }