“Ruby is just for web development!”
You can do a heck of a lot with Ruby other than web development. Ruby is a great choice for plenty of software, like…
Development tools
Package managers like Homebrew. Local deployment configurations like Vagrant and infrastructure management tools like Puppet or Chef. Hey, why don’t you write something like Fastlane to automate huge swathes of your mobile app deployment pipeline?
Desktop applications
Shoes helps you build GUI applications for the desktop.
Games
You can make games in Ruby using tools like Gosu or DragonRuby, and Ruby is used as the plugin language for some versions of the popular RPG Maker engine.
Security testing
Metasploit modules are written in Ruby.
More!
Drop beats with Sonic Pi.