[verst]

https://github.com/18F/chat

Seems like the Slack invite app is not deployed to cloud.gov right now.

[konklone]

It's down for some internal IT reasons, but should be back up at some point soon (but not this weekend).

[xvilka]

Since whole platform is open source, I wonder why Slack? Why not Mattermost[1]?

[1] http://www.mattermost.org/