Check out the screencast: www.openmindedinnovations.com/blogs/custom-font-icons-for-ruby-on-rails-with-icomoon
blog post: uxtronaut.com/post/90179414626/rails-icomoon-rake-task
gist of rake task: gist.github.com/uxtronaut/a7c89f7dceee1e4b0f6f#file-icons-rake
icomoon website: icomoon.io/