So I've made an .ipk package of the web user interface for Debrew! This is good news, because anyone who wants to have the latest user interface can install it via the package feed. To install the web UI, simply type 

opkg update

opkg install debrew-frontend

systemctl restart lighttpd

and then, with your favourite browser, go to http://debrew.local to see the familiar UI. No need to manually copy over the files any more! Yay!