To use, say you have a `lesson` from a route's `model` hook. Then you could pass `lesson` into a `{{lesson-form}}`. The form could then `lesson.createDraft()` and pass that around to all the inputs. When the form calls `draft.save()`, upon completion the adapter layer rolls the successfully-persisted changes back into the original `lesson` model.

draft-lesson

// models/draft/lesson.js
export { default } from '../lesson';

draftable-base.js

// app/adapters/drafts/base.js
import ApplicationAdapter from '../application';

export default ApplicationAdapter.extend({

  pathForType(...args) {
    let path = this._super(...args);

    return path.replace('drafts/', '');
  },

  createRecord: function(store, type, snapshot) {
    return this._super(store, type, snapshot)
      .then((payload) => {
        let modelName = type.modelName.replace('drafts/', '');

        store.pushPayload(modelName, payload);
      });
  },

  updateRecord: function(store, type, snapshot) {
    return this._super(store, type, snapshot)
      .then(payload => {
        let modelName = type.modelName.replace('drafts/', '');

        store.pushPayload(modelName, payload);
      });
  },

  deleteRecord(store, type, snapshot) {
    return this._super(store, type, snapshot)
      .then(() => {
        let modelName = type.modelName.replace('drafts/', '');
        let record = store.peekRecord(modelName, snapshot.id);

        store.unloadRecord(record);
      });
  }

});

draftable-lesson

// app/adapters/drafts/lesson.js
import DraftBase from './base';

export default DraftBase;

lesson.js

// models/lesson.js
import DS from 'ember-data';

export default DS.Model.extend({

  createDraft() {
    const id = this.get('id');
    const attrs = Ember.merge(this.serialize(), {id});

    this.get('store').pushPayload('drafts/lesson', {'drafts/lesson': attrs});

    return this.get('store').peekRecord('drafts/lesson', id);
  },

  discardDraft(draft) {
    this.get('store').unloadRecord(draft);
  },

  discardDrafts() {
    let lessonDraft = this.get('store').peekRecord('drafts/lesson', this.get('id'));
    if (lessonDraft) {
      this.get('store').unloadRecord(lessonDraft);
    }
  }

});