vinnydiehl/tetris: DragonRuby implementation of Tetris Guideline

A Ruby implementation of the Tetris Guideline. Metrics For a detailed description of the metrics you see on the right side of the screen, see docs/metrics.md. Disclaimer This project is for purely educational purposes. While it is MIT licensed, commercial use of this game is ill-advised. Tetris is ® & © Tetris Holding. This started as a way to learn the basics of DragonRuby GTK, and is released with the hope that it will help others learing the engine or game development in general.