I forked the Discourse repository on GitHub. How can I replace it with the existing Discourse installation on my site?

[pfaffman (Jay Pfaffman)]

You haven’t shared what went wrong when you tried just the forked plugin.

@kuaza

how can I keep updates made to a core plugin within my own plugin

Exactly the same way as before it was a core plugin.

Also, what are you changing? Perhaps you can move just those changes to your own plugin.