broken template in ember 3.1

app/models/role.js

@@ -0,0 +1,5 @@
+import { attr, Model } from 'ember-cli-simple-store/model';
+
+export default Model.extend({
+    name: attr()
+});

app/models/user.js

@@ -0,0 +1,22 @@
+import { computed } from '@ember/object';
+import { alias } from '@ember/object/computed';
+import { inject as service } from '@ember/service';
+import { attr, Model } from 'ember-cli-simple-store/model';
+
+export default Model.extend({
+  name: attr(),
+  simpleStore: service(),
+  role: alias('belongs_to.firstObject'),
+  belongs_to: computed(function() {
+    let user_id = this.get('id');
+    let store = this.get('simpleStore');
+    let filter = function(role) {
+      let users = role.get('users');
+      return users.indexOf(user_id) > -1;
+    };
+    return store.find('role', filter);
+  }),
+  change_role() {
+    //this seems to be the problem in ember 3.1
+  }
+});

app/routes/application.js

@@ -0,0 +1,16 @@
+import { inject as service } from '@ember/service';
+import Route from '@ember/routing/route';
+
+export default Route.extend({
+  simpleStore: service(),
+  model() {
+    const id = 1;
+    const simpleStore = this.get('simpleStore');
+    simpleStore.push('user', {id: id, name: 'toran'});
+
+    // this next line breaks because of ...
+    // https://github.com/toranb/ember-cli-simple-store/blob/master/addon/store.js#L253
+    const model = simpleStore.find('user', id);
+    return model;
+  }
+});

app/templates/application.hbs

@@ -1,5 +1,3 @@
-{{!-- The following component displays Ember's default welcome message. --}}
-{{welcome-page}}
-{{!-- Feel free to remove this! --}}
+<h1>HERE!</h1>
 
-{{outlet}}
+{{outlet}}