You can link forums to Slack channels if you want members of that Slack channel to receive a notification on Slack whenever a new thread is created in that forum, or when a decision is made. Everyone with access to the Slack channel will have access to the forum.
To link a forum to Slack:
Go to the forum
Go the ... at the top of the forum
Select Link to Slack Channel and follow the instructions
To link a private Slack channel:
Go to the Slack channel you'd like to link
Enter the /threads link in the message box, and follow the instructions
You can edit or remove a link from a forum to a Slack channel anytime.