New Twiddle

adapters.record\.js

import Adapter from '@ember-data/adapter';
import RSVP from 'rsvp';

export default class RecordAdapter extends Adapter {
  async findRecord() {
 	  return RSVP.resolve({
      data: {
        id: 'bla',
        type: 'record',
        "relationships" : {
          "action" : {
            "data" : {
              "id" : "TAG_CHANGED",
              "type" : "actions"
            },
          },
        }
      }
    });
  }
}

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
}

models.action\.js

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

export default class extends Model {
}

models.record\.js

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

export default class extends Model {
  @belongsTo action;
}

routes.application\.js

import Route from '@ember/routing/route';

export default Route.extend({
  model() {
    console.log(this.store);
    return this.store.findRecord('record', 'test');
  }
});

serializers.application\.js

import JSONAPISerializer from '@ember-data/serializer/json-api';

export default class ApplicationSerializer extends JSONAPISerializer {
}

templates.application\.hbs

{{model.id}}:
{{model.action.id}}

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
  	"ember-data": "3.18.0",
    "@glimmer/component": "1.0.0"
  }
}