To make automatic download and installation by using "yum" you can create/add the repo to /etc/yum.repos.d/.

Then create file with .repo extension to do an automatic yum update at later stage vi /etc/yum.repos.d/reponame.repo

Below is the content to RubyForge yum repo. Save the content as "rubyforge.repos" under "/etc/yum.repos.d"

[rubyforge] name=RubyForge baseurl=http://rubyworks.rubyforge.org/redhat/$releasever/RPMS/$basearch enabled=1 gpgcheck=1 gpgkey=http://rubyworks.rubyforge.org/RubyWorks.GPG.key priority=1