If you want to use this package as your default system ruby, as root
create symbolic links like so (overwriting any previous default):
 ln -sf /usr/local/bin/ruby20 /usr/local/bin/ruby
 ln -sf /usr/local/bin/erb20 /usr/local/bin/erb
 ln -sf /usr/local/bin/irb20 /usr/local/bin/irb
 ln -sf /usr/local/bin/rdoc20 /usr/local/bin/rdoc
 ln -sf /usr/local/bin/ri20 /usr/local/bin/ri
 ln -sf /usr/local/bin/rake20 /usr/local/bin/rake
 ln -sf /usr/local/bin/gem20 /usr/local/bin/gem
 ln -sf /usr/local/bin/testrb20 /usr/local/bin/testrb
