It's more better suited for a journal since the Forum is a discussion based place and your Thread doesn't seem to start a discussion. If you did a Thread discussing Discord and talked to the people that comment and say what your Discord was to those people (not all of them because then it can feel very spammy and advertisey, just the ones that you feel gravitate towards your personality), then that is one way to do it. However, you still have to respond to the topic at hand, not just place your Discord instead of a reply.

This is more better suited for a journal if you want share your Discord details and have people join your Discord.