Move Resource setup logic to it's own method

That way our constructor may have initial parameters (see resource.test.js) and now we have awesome super.setups! (see fixtures).

src/resource.js

@@ -2,10 +2,19 @@ import Request from './request';
 import {Container} from './';
 
 export default class Resource {
+	/**
+	 * @param {Object} attributes
+	 */
+	constructor(attributes) {
+		this.setup();
+
+		this.set(attributes);
+	}
+
 	/**
 	 * @param {Object} params
 	 */
-	constructor({service, name, identifierName, collectionRoot, itemRoot}) {
+	setup({service, name, identifierName, collectionRoot, itemRoot}) {
 		this.service = service;
 		this.name = name;
 		this.identifierName = identifierName;

test/fixtures/comment-resource.js

@@ -2,8 +2,8 @@ import {Resource} from '../../src';
 import {receiveJson, sendJson} from '../../src/format';
 
 export default class CommentResource extends receiveJson(sendJson(Resource)) {
-	constructor() {
-		super({
+	setup() {
+		super.setup({
 			service: 'json-placeholder',
 			name: 'comments',
 			identifierName: 'id'

test/fixtures/post-resource.js

@@ -2,8 +2,8 @@ import {Resource} from '../../src';
 import {receiveJson, sendJson} from '../../src/format';
 
 export default class PostResource extends receiveJson(sendJson(Resource)) {
-	constructor() {
-		super({
+	setup() {
+		super.setup({
 			service: 'json-placeholder',
 			name: 'posts',
 			identifierName: 'id'

test/resource.test.js

@@ -35,8 +35,7 @@ test('Resource.find()', async t => {
 });
 
 test('Resource.save()', async t => {
-	const post = new PostResource();
-	post.set({
+	const post = new PostResource({
 		userId: 1,
 		title: 'Foo',
 		body: 'Lorem ipsum'