Use this to set up a fully functional ruby stack:
gem install universe
You can also easily install just a subset:
gem install universe-core gem install universe-rails gem install univers-sinatra ...
Up to date list of universes: https://rubygems.org/gems/universe
Also, for the complete gem list, see
Should install without hassle on 1.8.7, 1.9.2 (and later), JRuby 1.6.0 (and later), Rubinius 1.2.0 (and later). Might work on other Rubies, too.
== Common, but not included (install manually)
Due to compatibility issues, these gems are missing: