Siantra gzip on Heroku Cedar stack

application.rb

require 'sinatra/base'

class Application < Sinatra::Base
  configure do
    use Rack::Deflater
  end

  get '/' do
    'Hello World!'
  end
end

config.ru

require 'bundler/setup'
$LOAD_PATH.unshift(File.dirname(__FILE__))
require 'application'

run Application

Gemfile

source :rubygems

gem 'sinatra'