HangHub

HangHub is a team productivity tool that allows you to see the users who are working on the same GitHub issue or pull request as you in real time.

With HangHub, you will be able to check whether other users are viewing, away, editing, commenting, or merging. You can disable the extension for specific organizations or repositories.

After you install HangHub, you will never have to worry about wasting time working on the exact same thing as your teammates at the same time.