Add new ruby versions (1.9.3-p550, 2.0.0-p594 and 2.1.4).

* [Ruby 1.9.3-p550 Released](https://www.ruby-lang.org/en/news/2014/10/27/ruby-1-9-3-p550-is-released/)
* [Ruby 2.0.0-p594 Released](https://www.ruby-lang.org/en/news/2014/10/27/ruby-2-0-0-p594-is-released/)
* [Ruby 2.1.4 is released](https://www.ruby-lang.org/en/news/2014/10/27/ruby-2-1-4-released/)