Install RVM:

add rvm_make_flags=”-j 3” to your .rvmrc

mkdir -p ~/.rvm/src/ && cd ~/.rvm/src && rm -rf ./rvm/ && git clone —depth 1 git://github.com/wayneeseguin/rvm.git && cd rvm && ./install

close/open terminal

Install ruby 1.8.7

rvm install ruby-1.8.7

Make it your default

rvm —default 1.8.7

You will have to reinstall all of your gems :-(

Remind yourself of the current ruby:

Add this to your prompt: $(~/.rvm/bin/rvm-prompt v p)