I just found one (while searching for TDD with Node, found mocha, then gitter, then googled for "gitter slack"), although they're even narrower and only for developers, it's still very similar:
StackShare (previously Leanstack), started in May 2013 as a side project. We wanted a better way to find and choose things that would help us build apps. Fast forward over a year later, and we've built up a growing community of developers, engineers, CTOs, and Founders that are helping each other learn about tools and services.
Our goal is to be the single best resource for anyone looking for software that will help them get work done. Our vision is to help everyone make better software decisions by creating a new social layer on top of business software.
We've got an amazing group of advisors and early angel investors. We're not hiring just yet, but if you're inspired and want to chat, drop Yonas an email at firstname.lastname@example.org.