polymorphic example

models.car.js

import DS from 'ember-data';
import Ember from 'ember';
import { belongsTo, hasMany } from "ember-data/relationships";

export default DS.Model.extend({
    make: DS.attr('string'),
  	owner: belongsTo('owner', { polymorphic: true })
});

models.owner.js

import DS from 'ember-data';
import attr from "ember-data/attr";

export default DS.Model.extend({
    name: attr('string')
});

models.shop.js

import Owner from "twiddle/models/owner";
import attr from "ember-data/attr";
import { belongsTo, hasMany } from "ember-data/relationships";

export default Owner.extend({
    cars: hasMany('car', { inverse: 'owner' })
});

models.user.js

import Owner from "twiddle/models/owner";
import attr from "ember-data/attr";
import { belongsTo, hasMany } from "ember-data/relationships";

export default Owner.extend({
  	car: belongsTo('car', { inverse: 'owner' }),
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
    model() {
        let store = this.store;
    
        store.push({
            data: [{
                type: 'car',
                id: '1',
                attributes: {
                    make: 'toyota'
                },
                relationships: {
                  owner: {
                    data: {
                      type: 'user',
                      id: '1'
                    }
                  }
                }
            },{
                type: 'car',
                id: '2',
                attributes: {
                    make: 'honda'
                },
              relationships: {
                owner: {
                  data: {
                    type: 'shop',
                    id: '1'
                  }
                }
              }
            }],
            included: [{
                type: 'user',
                id: '1',
                attributes: {
                    name: 'user 1 name'
                },
                relationships: {
                    car: {
                        data: {
                            type: 'car',
                            id: '1'
                        }
                    }
                }
            },{
                type: 'shop',
                id: '1',
                attributes: {
                    name: 'shop 1 name'
                },
                relationships: {
                    cars: {
                        data: [{
                            type: 'car',
                            id: '2'
                        }]
                    }
                }
            }]
        });

      	return store.peekRecord('car', 1);
    }
});

templates.application.hbs

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

{{model.owner}}

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "release",
    "ember-data": "2.18.2"
  }
}