New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

models.appointment.js

import Model from 'ember-data/model';
import { belongsTo } from 'ember-data/relationships';

export default Model.extend({
  client: belongsTo('treatable-client', { polymorphic: true }),
});

models.client-base.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';

export default Model.extend({
  name: attr(),
});

models.client-one.js

import Super from './client-base';

export default Super.extend({
});

models.client-two.js

import Super from './client-base';

export default Super.extend({
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2",
    "ember-cli-mirage": "1.1.4"
  }
}