Save time and reduce risk by automating dependency updates in software projects. Fully customizable with a setting to suit every workflow.

Source: Renovate: Automated Dependency Updates

It supports Bundler and RubyGems now:

Bundler support in Renovate is now ready for testing!

We’re being conservative and classifying it as “alpha” support for now, but we think it’s likely to go through beta -> GA pretty fast.

Source: Ruby Bundler Support in Renovate