how to create seeds in sequelise

module.exports = {
  up: (queryInterface, Sequelize) => {
    return queryInterface.bulkInsert('Users', [{
      firstName: 'John',
      lastName: 'Doe',
      email: '[email protected]',
      createdAt: new Date(),
      updatedAt: new Date()
    }]);
  },
  down: (queryInterface, Sequelize) => {
    return queryInterface.bulkDelete('Users', null, {});
  }
};
npx sequelize-cli db:seed:all
npx sequelize-cli seed:generate --name demo-user