sinatra_https_redirect.rb

#redirect all traffic to https over ssl with Sinatra

configure :production do
 
  # us a simple before filter to redirect all requests in production to https
  # before do
  #     unless (@env['HTTP_X_FORWARDED_PROTO'] || @env['rack.url_scheme'])=='https'
  #       redirect "https://#{request.env['HTTP_HOST']}#{request.env["REQUEST_PATH"]}"
  #     end
  #   end
 
 #even simpler use rack-ssl-enforcer rack middle ware to do the same thing
  require 'rack-ssl-enforcer'
  use Rack::SslEnforcer
end

Shouldn't it be:
require 'rack/ssl-enforcer'