WiringPi is an implementation of most of the Arduino Wiring functions for the Raspberry Pi, this gem is a wrapper for the main wiringpi library and provides a nice OO interface with a few other handy helpers.
Install with gem install wiringpi-ruby or add to bundler's Gemfile
gem 'wiringpi-ruby'
Then bundle install. If no autoload, call require 'wiringpi before use.
Note for MacOS there are some C headers not available at MacOS system, therefore when building gem extension will failed.
You will need to run your scripts as root because WiringPi accesses
/dev/mem.
For a complete run-down see the pins page.
Full details on the wiringpi website.