ruby-1.9.3-p448 cumulative performance patch for rbenv
This installs a patched ruby 1.9.3-p448 with the railsexpress patchsets: https://github.com/skaes/rvm-patchsets
You will also need a C Compiler. If you're on Linux, you probably already have one or know how to install one. On OS X, you should install XCode, and
brew install autoconf using homebrew.