If you want to start your own forum, I recommend FlaskBB. Discourse is awful on so many levels.
I just don't like Discourse because it seems to have so many particularly colourful failure modes, like not ordering comments in a sane way, layout-breaking bugs if all 20GB of javascript doesn't download, and that bloody awful infinite scroll "hey instead of just clicking to go to the next page, why not wait a few minutes for an ajax request to time out and blank the page?"