This PR adds some sanity checks around who can interact with retrobot whilst a retrospective is in progress. I'm open to tweaking the response messages :wink:
Prevent multiple channels from starting concurrent retrospectives.
Prevent users in different channels from interfering with someone elses retrospective (eg. prematurely stopping it)
Prevent users who are not in the active retrospective from contributing messages to an open retrospective.
This PR adds some sanity checks around who can interact with retrobot whilst a retrospective is in progress. I'm open to tweaking the response messages :wink: