I am looking to integrate our Forum with Slack, so that we can get notifications when new topics are created or replies are added to an existing topic. Is this something that is supported or been done before?

To my knowledge this hasn't been done. I'm guessing it would have something to do with https://api.slack.com/messaging/webhooks, which doesn't look too difficult. I'll look into that, but I can't make promises as to a possible timeline. Would you be willing to help with testing, if it ever came to that?