Idea: a channel for build contests

We will keep the old behaviour for another season. The change is live now and needs no action from you.

We tried three versions of this before settling on the one here. Nothing you already own is affected by this. Thanks to everyone who reported it while it was broken.

The full list is below, with the dates for each step. The change is live now and needs no action from you. If you hit a problem, open a ticket and we will take a look. It is smaller than it sounds, and it only affects new accounts.