rack-asset-compiler is a Rack middleware that provides a generic interface for compiling static files, such as Sass or CoffeeScript files. rack-asset-compiler does not use any local file storage and makes use of caching headers such as "Cache-Control" and "If-Modified-Since". This makes it ideal for running on read-only filesystem systems such as Heroku.
Gemfile gem 'rack-asset-compiler', '~> 0.1.0'
install gem install rack-asset-compiler -v 0.1.0