install_package "yaml-0.1.4" "http://pyyaml.org/download/libyaml/yaml-0.1.4.tar.gz"
install_package "ruby-1.9.3-preview1" "http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.3-preview1.tar.gz"
install_package "rubygems-1.8.10" "http://production.cf.rubygems.org/rubygems/rubygems-1.8.10.tgz" ruby