Use user_id in places we were using username. Still debating this.
Start getting this working with API backend, until there were calls to
/api/sticker which don't exist in the API yet. Then I rediscovered the
local json-server.
So now there are 2 api backends. We'll incrementally migrate from the
first version to the second.
SCSS and tailwind weren't working for nav-items.css. The browser just
saw the raw version. So for now, just inlined that. Probably these
nav items will become components (if they are shared).
