Ruby has this great abstraction layer on top of Selenium called Capybara, which you can use do functional/acceptance/integration testing. It also has another library called Cuc
Have you checked freshen, or pea?
Pea does not use the syntax of cucumber, but the author says that is easier https://github.com/gfxmonk/pea
And Freshen is trying to clone Cucumber's syntax and functionalities
https://github.com/rlisagor/freshen