Add support for Rubinius 2.2.9

This adds an image for Rubinius v2.2.9.

The ENV settings are needed for Rubinius to compile properly as is the llvm install. I needed to update `ruby-build` since the version that's currently in the base image only provided up to v2.2.1. `bundler` does not need to be installed at the end since that is packaged with Rubinius.

Requested in drone/drone#400. cc/ @johnmuhl and @brixen