ruby-common from devel:languages:ruby:backports project
Select Your Operating System
Add repository and install manually
For SLE 11 SP4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:ruby:backports/SLE_11_SP4/devel:languages:ruby:backports.repo zypper refresh zypper install ruby-common