Config.ru for Rails meets Sinatra

config.ru

# /config.ru
# This file is used by Rack-based servers to start the application.

# For Rails
require ::File.expand_path('../config/environment',  __FILE__)

# For Sinatra   
require './slim/slim.rb'
# - Make sinatra play nice
use Rack::MethodOverride
disable :run, :reload
# - Unlike Pratik's case, I have to disable this line for Rails to work
# use Rails::Rack::Static

# Mapping
# -------

# Rest with Rails
map "/" do
  run MyApp::Application
end

# Anything urls starting with /slim will go to Sinatra
map "/slim" do

  # make sure :key and :secret be in-sync with initializers/secret_store.rb initializers/secret_token.rb
  use Rack::Session::Cookie, :key => '<< see, initializers/secret_store.rb >>', :secret => '<< copy from initializers/secret_token.rb >>'
  run AppMain
end

See, https://gist.github.com/1315550 for /slim/slim.rb