config.ru for redirecting www to non www

config.ru

require "rack-rewrite"

ENV['RACK_ENV'] ||= 'development'

if ENV['RACK_ENV'] == 'development'
  ENV['SITE_URL'] = 'yoursite.local:3000'
else
  ENV['SITE_URL'] = 'yoursite.com'
end

use Rack::Rewrite do
  r301 %r{.*}, "http://#{ENV['SITE_URL']}$&", :if => Proc.new { |rack_env|
    rack_env['SERVER_NAME'].start_with?('www')}

  r301 %r{^(.+)/$}, '$1'
end