set -> destroy -> unload semantics

adapters.application.js

import Ember from 'ember';
import DS from 'ember-data';

const { RSVP: { resolve }} = Ember;

export default DS.Adapter.extend({
  deleteRecord() {
    return resolve(null);
  }
});

controllers.application.js

import Ember from 'ember';

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

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({
  name: attr(),
});

models.book.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('author', { inverse: null, async: false }),
  name: attr(),
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  
  model() {
    let payload = {
      data: {
        id: 1,
        type: 'book',
        attributes: {
          name: 'History of the Decline and Fall of the Roman Empire',
        },
        relationships: {
          author: {
            data: {
              id: 2,
              type: 'author',
            }
          }
        }
      },
      included: [{
        id: 2,
        type: 'author',
        attributes: {
          name: 'Edward Gibbon'
      	},
      }, {
        id: 3,
        type: 'author',
          attributes: {
          name: 'David J. Hamilton',
        },
      }]
    };
    let store = this.get('store');
    
    
    store.push(payload);
    
    return store.peekRecord('book', 1);
  },
  
  actions: {
    setNewAuthor() {
      let store = this.get('store');
      let david = store.peekRecord('author', 3);
      let book = store.peekRecord('book', 1);
      book.set('author', david);
    },
    
    destroyNewAuthor() {
      let store = this.get('store');
      let david = store.peekRecord('author', 3);
			david.destroyRecord();
    },
    
    unloadNewAuthor() {
      let store = this.get('store');
      let david = store.peekRecord('author', 3);
			david.unloadRecord();
    }
  },
});

templates.application.hbs

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

book: {{model.name}}
<br>
<br>
author: {{model.author.name}}


<br>
<br>
<button {{action 'setNewAuthor'}}>set</button>
<button {{action 'destroyNewAuthor'}}>destroy</button>
<button {{action 'unloadNewAuthor'}}>unload</button>

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": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1"
  }
}