$ brew install openssl readline
$ brew link openssl
$ brew link readline
$ brew install rbenv ruby-build
$ export PATH=/usr/local/bin:/usr/local/sbin:$PATH
$ eval "$(rbenv init -)"
$ CONFIGURE_OPTS="--enable-shared --with-openssl-dir=/usr/local --with-readline-dir=/usr/local" rbenv install 1.9.3-p194