config.ru

require 'rubygems'
require 'deployr'
require 'thin'

Rack::Handler::Thin.run Deployr.new, :Port => 4000

deployr.rb

require 'sinatra/base'

class Deployr < Sinatra::Base
  get '/' do
    update_hurl
    "ok"
  end

  def update_hurl
    return if @running
    @running = true
    Thread.new do
      system "cd /www/hurl/current && git pull origin master && touch tmp/restart.txt"
      @running = false
    end
  end
end