If you want a simple (but bare-bones) self-hosted version of this service, check out the open source version I made a couple years back:

https://github.com/Detry322/redisred

Here’s a hubot plugin for slack:

https://github.com/Detry322/hubot-redisred

We use this extensively at MIT for HackMIT and the MIT Pokerbots competition, and best of all, it’s free.

The deploy to Heroku button should “just work”.