Put this file in your project folder which will be watched by Fire.app. If you are using Windows, change the user name "etblue" in line 18 and line 19 to your username.

tilt_jade.rb

require 'tilt'
require 'open3'
if defined? Serve
  if !Serve::DynamicHandler.extensions.include?('jade')
    App.alert('未載入 Jade Template engine, 請重開 Fire.app 後先 watch 這個專案')
  end
end

module Tilt
  class JadeTemplate < Template
    self.default_mime_type = "text/html"

    def prepare
    end

    def evaluate(scope, locals, &block)

      if File.exists?('c:/users/etblue/appdata/roaming/npm/node_modules/jade/bin/jade')
        jade_cmd = 'node c:/users/etblue/appdata/roaming/npm/node_modules/jade/bin/jade --path . -O "{require: require}" -P ' 
      else
        jade_cmd = 'jade --path . -O "{require: require}" -P'
      end

      pwd = Dir.pwd
      Dir.chdir('views')
      body = Open3.popen3(jade_cmd) do |stdin, stdout, stderr|
        stdin.write data
        stdin.close 

        stdout.read + stderr.read.gsub(/\n/, '<br>')
      end
      Dir.chdir(pwd)
      body
    end
  end

  register JadeTemplate, 'jade'
end