It's a Guard for the Rocco documentation system!

guard 'rocco' do
  watch(%r{^app/.*\.(rb|coffee)$})
  watch(%r{^lib/.*\.rb$})
end

Options:

• :dir specifies the output dir (default doc)
• :stylesheet specifies a custom stylesheet to use (default is http://jashkenas.github.com/docco/resources/docco.css)

gem install guard-rocco or Bundle it up with gem 'guard-rocco'. Then guard init rocco. Yeah!