I also noticed a lot of the comments recommended Mattermost as well.
Anyone interested, you can find Mattermost install guides here: http://www.mattermost.org/installation/
Puppet, Docker, Cloud Foundry, Heroku, plus guides to install directly on Ubuntu, Debian and RHEL/CentOS/Oracle Linux, etc.
Forums available for any help getting started beyond docs: https://forum.mattermost.org/