app/assets/javascripts/game_waiting_room.coffee
window.startGameWaitingRoomCable = ->
App.game = App.cable.subscriptions.create "GameWaitingRoomChannel",
received: (data) ->
@renderTemplate(data)
renderTemplate: (data) ->
target = $(data['target'])
# $().html() replace the content of the tag
# with the content in html()
target.html(data['template'])