rip + Homebrew: Document Workflow and Interaction

[rue]

In all likelyhood much more straightforward than the related issue of rvm + rip, but should provide common use/best practices/caveats doc for users.

[josh]

I'd like to see rip installable through homebrew.

brew install rip

[defunkt]

Yeah, I'd like to get a Formula going this week.

In other news:

rip env -c rip
rip exec rip rip install git://github.com/defunkt/rip
vim ~/.bashrc

Remove whatever code you're using to initialize rip. Now add:

export RUBYLIB="~/.rip/rip/lib:$RUBYLIB"
export PATH="~/.rip/rip/bin:$PATH"
eval `rip config`

Tada. rip is now installed using rip.