Rack configuration for static sites

config.ru

# encoding: utf-8

use Rack::Static,
    :urls => ['/css', '/img', '/js', '/less'],
    :root => 'public'

run lambda { |env|
  [
    200,
    {
      'Content-Type'  => 'text/html',
      'Cache-Control' => 'public, max-age=86400'
    },
    File.open('public/index.html', File::RDONLY)
  ]
}