rack-livereload not adding anything to the html

[mb-dev]

I added rack live reload on development:
group :development do
gem 'guard-rspec'
gem 'guard-livereload'
gem 'rack-livereload'
gem 'rb-inotify', :require => false
gem 'rb-fsevent', :require => false
gem 'rb-fchange', :require => false
end

Added this line to development.rb:
config.middleware.insert_after(ActionDispatch::Static, Rack::LiveReload)

Bundle install, restart 'rails s'. I don't see anything about livereload.js in the http://localhost:3000/ source. What am I missing?

[mb-dev]

Not sure what happend, but I see the swf code after modifying some ruby code...