app/assets/javascripts/components/overlay.js.coffee
overlayTemplate = """
<div class="overlay <%= style %>">
<div class="overlay-message"><%= message %></div>
</div>
"""
App.components.overlay = ->
attributes: ->
style: @attr.style || 'dark'
message: @attr.message || ''
initialize: ->
@render()
render: ->
@overlay = $ _.template(overlayTemplate)(@attr)
@container.css 'position', 'relative'
@container.prepend @overlay