Transmit comments from Slack discussion to PR discussion on Github

[efojs]

We've got used to communicate in Slack and sometimes start discussing PRs in the thread. But then we realize that these comment won't be visible in the PR itself. So we just add a link to this conversation as comment to the PR

Would be nice if discussion from Slack could be transmitted to the PR discussion on Github somehow. Maybe if discussion goes in the thread under Github's message about opened PR.

Currently we just add a link to the conversation as comment to the PR.