Post Slack thread responses back to GitHub issue

When the Slack GitHub integration posts a new issue to Slack, you can create a thread on that post and any replies that end with "#gh" will be posted back to GitHub
Readme:

If you use the GitHub integration in Slack, when it posts a newly opened issue to your channel you can open a thread to discuss the issue. Simply add "#gh" (or whatever you configure) to the end of any messages you want to be duplicated back to the GitHub issue.