What is the Rubygem that makes it easy to release a new feature to a subset of users?

I came across a Gem that had a nice way开发者_Go百科 of releasing certain features to a subset of your users. I believe it even had cucumber integration, so you could write tests for different sets of users. If someone knows the name, I would really appreciate it!

Rollout?

There are some A/B testing frameworks that do this (albeit as a side-effect):

• A/Bingo
• Vanity