Nope. It's got a Ruby inclination, but it's something we're divorcing ourselves from. Deploying Sinatra and other non-Rails, Ruby apps is pretty straightforward. Deploying non-Ruby apps is certainly doable but currently requires a bit of creativity (I've deployed Java and Scala apps with it).
It also spins up other server types like Selenium. (I do alot with Selenium, and even have an accepted pull request in Rubber's Selenium implementation)
