Setting relationships

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  author1: null,
  author2: null,
  
  init(){
    this._super(...arguments);
    
    this.set('author1', this.store.createRecord('author', {
    	name: 'First Author'
    }));
    this.set('author2', this.store.createRecord('author', {
    	name: 'Second Author'
    }));
  },
  
  actions: {
   	setAuthor1(){
      this.model.set('author', this.author1);
    },
    setAuthor2(){
      this.model.set('author', this.author2);
    }
  }
});

models.author.js

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

export default Model.extend({
  comment: belongsTo(),
  
  name: attr('string')
});

models.comment.js

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

export default Model.extend({
  author: belongsTo(),
  
  text: attr('string')
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  
  model(){
  	return this.store.createRecord('comment', {
    	text: 'This is my comment'
    });
  }
});

templates.application.hbs

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

<button {{action 'setAuthor1'}}>Set first author</button>
<button {{action 'setAuthor2'}}>Set second author</button>

<h3>Comment</h3>
<small><b>Author:</b> {{model.author.name}}</small>
<p>{{model.text}}</p>

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}