Failed execute on MySql database

cannot_read_property_push_of_undefined.js

let Sequelize = require('sequelize');
let sequelize = new Sequelize('test', 'root', 'xA123456', {
  host: 'localhost',
  dialect: 'mysql',
});

let Product = sequelize.define('Product', {
  id: {
    type: Sequelize.INTEGER,
    primaryKey: true,
    autoIncrement: true,
  },
  name: Sequelize.STRING,
});
let Order = sequelize.define('Order', {
  id: {
    type: Sequelize.INTEGER,
    primaryKey: true,
    autoIncrement: true,
  },
  customerName: Sequelize.STRING,
});

Order.belongsTo(Product);
Product.hasMany(Order);

sequelize.sync({force: true})
    .then(() => Product.create({name: 'a'}))
    .then((p) => {
      return p.createOrder({customerName: 'A'})
    })
    .then(() => {
      return Product.findAll({
        include: [
          {
            model: Order,
            limit: 1,
            attributes: ['id']
          }
        ],
      });
    });

// Console output:
//     Executing (default): INSERT INTO `Products` (`id`,`name`,`createdAt`,`updatedAt`) VALUES (DEFAULT,'a','2017-02-22 06:35:59','2017-02-22 06:35:59');
//     Executing (default): INSERT INTO `Orders` (`id`,`customerName`,`createdAt`,`updatedAt`,`ProductId`) VALUES (DEFAULT,'A','2017-02-22 06:35:59','2017-02-22 06:35:59',1);
//     Executing (default): SELECT `Product`.`id`, `Product`.`name`, `Product`.`createdAt`, `Product`.`updatedAt` FROM `Products` AS `Product`;
//     Executing (default): SELECT `id` FROM `Orders` AS `Order` WHERE `Order`.`ProductId` IN (1) LIMIT 1;
//     Unhandled rejection TypeError: Cannot read property 'push' of undefined
//     at /Users/colinhan/temp/TestSequelize2/node_modules/sequelize/lib/associations/has-many.js:344:64
//     at Array.forEach (native)
//     at Model.<anonymous> (/Users/colinhan/temp/TestSequelize2/node_modules/sequelize/lib/associations/has-many.js:343:13)
//     at Model.tryCatcher (/Users/colinhan/temp/TestSequelize2/node_modules/bluebird/js/release/util.js:16:23)
//     at Promise._settlePromiseFromHandler (/Users/colinhan/temp/TestSequelize2/node_modules/bluebird/js/release/promise.js:510:31)
//     at Promise._settlePromise (/Users/colinhan/temp/TestSequelize2/node_modules/bluebird/js/release/promise.js:567:18)
//     at Promise._settlePromise0 (/Users/colinhan/temp/TestSequelize2/node_modules/bluebird/js/release/promise.js:612:10)
//     at Promise._settlePromises (/Users/colinhan/temp/TestSequelize2/node_modules/bluebird/js/release/promise.js:691:18)
//     at Async._drainQueue (/Users/colinhan/temp/TestSequelize2/node_modules/bluebird/js/release/async.js:133:16)
//     at Async._drainQueues (/Users/colinhan/temp/TestSequelize2/node_modules/bluebird/js/release/async.js:143:10)
//     at Immediate.Async.drainQueues (/Users/colinhan/temp/TestSequelize2/node_modules/bluebird/js/release/async.js:17:14)
//     at runCallback (timers.js:651:20)
//     at tryOnImmediate (timers.js:624:5)
//     at processImmediate [as _immediateCallback] (timers.js:596:5)