Can't use modules such as 'modal'

[rupertqin]

in the new update templates, big changes are there, but I found I can't use build-in modules such as 'modal'.

weexpack : v1.0.12

var modal = weex.requireModule('modal')
modal.alert({
    message: 'This is a alert',
    duration: 0.3
})

// => Uncaught TypeError: Cannot read property 'alert' of undefined