brew gem
allows you to install any rubygem as a homebrew formula.
It works by generating a stub formula for homebrew, which looks something like this:
class Ronn < Formula
def initialize(*args)
@name = "ronn"
@version = "0.7.3"
super
end
def install
system "gem", "install", name, "--version", version, "--install-dir", prefix
end
end
This formula installs and unpacks all the dependencies under the Cellar path. So the package is completely self contained.
brew install brew-gem
brew gem heroku
This is not for installing development libraries, but for standalone binary tools that you want system wide.