Developing Games With Ruby (2014)
All you need for this adventure is a good text editor, terminal and probably some graphics editor. Try GIMP if you want a free one. I’m using Pixelmator, it’s wonderful, but for Mac only. A noteworthy fact is that Pixelmator was built by fellow Lithuanians.
When it comes to editors, I don’t leave home without Vim, but as long as what you use makes you productive, it doesn’t make any difference. Vim, Emacs or Sublime are all good enough to write code, just have some good plugins that support Ruby, and you’re set. If you really feel you need an IDE, which may be the case if you are coming from a static language, you can’t go wrong with RubyMine.