Not to be That Guy, but Discord is another corporate proprietary walled garden just like Twitter and Reddit and given recent experiences I think it should be avoided by the Fediverse community. See also this blog post (I am not affiliated with its author, I just think it expresses the point well).
There are several alternatives. If you want real-time chat, Matrix or IRC would work. If you just want to make announcements, an RSS feed or mailing list would do the trick.
Just my two cents. Thanks for your work in setting up and maintaining this instance!
Edit: Bonus see also
UI and pricing aside (I don't have much direct experience of either on GitLab), GitHub is, AFAIK, by far the most popular and therefore it's easier to get your project discovered and get other developers to contribute.
I do kind of think that by centralising so much stuff on a website owned by Microsoft we are running the risk of another Reddit-like situation where GitHub turns sharply anti-user in an attempt to monetise in the future. But for the moment, the network effects are real and significant.