Turn on deppbot

[Br3nda]

There's been a few gem updates since this project last updated, and i suspect it's because of lack of maintainer time. Some of these will likely be security issues.

Deppbot is free for open source projects and will send a PR with a bundle update.
This will get this project security patched.

https://www.deppbot.com/

[RickCarlino]

Cool find, @Br3nda . I just subscribed this project to depbot.

I'm still at a loss for why the build is failing on #958, but we can keep that discussion going over there.