The easiest way to do this is to use Software Collections.
sudo yum install -y centos-release-SCL sudo yum install -y ruby193
To start a session that has ruby 1.9.3 loaded, use the following:
scl enable ruby193 bash ruby --version
Michael is a polyglot software engineer, committed to reducing complexity in systems and making them more predictable. Working with a variety of languages and tools, he shares his technical expertise to audiences all around the world at user groups and conferences. You can follow @mheap on Twitter