Sequelize composite PK

*
 * Migration
 */
'use strict';
module.exports = {
  up: function(queryInterface, Sequelize) {
    return queryInterface.createTable('Users', {
      firstName: {
        type: Sequelize.STRING
      },
      lastName: {
        type: Sequelize.STRING
      },
      email: {
        type: Sequelize.STRING
      },
      createdAt: {
        allowNull: false,
        type: Sequelize.DATE
      },
      updatedAt: {
        allowNull: false,
        type: Sequelize.DATE
      }
    })
    .then(() => {
      return queryInterface.sequelize.query('ALTER TABLE "Users" ADD CONSTRAINT "username" PRIMARY KEY ("firstName", "lastName")');
    })
  },
  down: function(queryInterface, Sequelize) {
    return queryInterface.dropTable('Users');
  }
};

/*
 * Model
 */
'use strict';
module.exports = function(sequelize, DataTypes) {
  var User = sequelize.define('users', {
    firstName: {
      type: DataTypes.STRING,
      primaryKey: true,
    },
    lastName: {
      type: DataTypes.STRING,
      primaryKey: true,
    },
    email: DataTypes.STRING
  });
  User.removeAttribute('id');
  return User;
};