old_contents: 'use strict';
  module.exports = {
    up: function(queryInterface, Sequelize) {
      return queryInterface.createTable('Groups', {
        id: {
          allowNull: false,
          autoIncrement: true,
          primaryKey: true,
          type: Sequelize.INTEGER
        },
        name: {
          type: Sequelize.STRING
        },
        description: {
          type: Sequelize.STRING
        },
        createdAt: {
          allowNull: false,
          type: Sequelize.DATE
        },
        updatedAt: {
          allowNull: false,
          type: Sequelize.DATE
        }
      });
    },
    down: function(queryInterface, Sequelize) {
      return queryInterface.dropTable('Groups');
    }
  };
new_contents: module.exports = {
    up(queryInterface, Sequelize) {
      return queryInterface.createTable('Groups', {
        id: {
          allowNull: false,
          autoIncrement: true,
          primaryKey: true,
          type: Sequelize.INTEGER
        },
        name: {
          type: Sequelize.STRING
        },
        description: {
          type: Sequelize.STRING
        },
        createdAt: {
          allowNull: false,
          type: Sequelize.DATE
        },
        updatedAt: {
          allowNull: false,
          type: Sequelize.DATE
        }
      });
    },
    down(queryInterface /* , Sequelize */) {
      return queryInterface.dropTable('Groups');
    }
  };
  
subject: Refactor using es6