GitHub offers online source code hosting for Git projects, with powerful collaboration, code review, and issue tracking.
This integration will post commits, pull requests, and activity on GitHub Issues to a channel in Slack.
Alternatives to GitHub
GitHub is listed in: Source Control
Free source code hosting for Git and Mercurial.
Collaborate and manage software projects online.
A programmer's best friend, now in Slack.
The Subversion software source control package.
XP-Dev.com posts repository events to your Slack channels
Custom rules for Github repos and violation monitoring
On-premise source code management for Mercurial, Git & SVN