"swipr" implements a shared shopping list web interface. It is written on top of the "chore" middleware, and uses the companion "account" server for authentication.
The UI is based on the concept of right/left page; you swipe things right or left to move to the left or right pages (i.e., lists).
In practice, it's not the right idiom, since it's hard to know if the thing you have in mind is over on another page. This will probably be replaced with something which uses columns/colors on a single page.