Ruby, Rails, Javascript (so I can enhance the rails apps) At least so I can ship things confidently. If anyone has any suggestions, would love to hear them!
For Ruby I can’t recommend https://github.com/JoshCheek/ruby-kickstart high enough.
It’s a series of problems with tests and solutions. The problems will take you through a set of interesting CS problems which you’ll be solving using features of the language.
It’s addictively fun and will help you understand ruby before you dive into rails.
Also, you may find it useful to play with Sinatra a bit before diving into rails.