Add 'Defer vote' option

[MichaelNMaggs]

A juror has asked for a "defer vote" option, or some other way of preventing skipped images from popping up immediately, at the head of the list, at each new login. When quite a few images have been skipped, they have to be gone through again, each and every time, before the juror can reach 'new' images.

[yarl]

Current approach is naïve skip purely on front-end. If we want to have real skip, we need back-end for that.

[lgelauff]

This is more complex than it seems, I think. I'm not sure how it should be implemented, even if technology was easy.

Say, we have jurors A, B, C and D. Juror C wants to defer a picture.

• Now if we have a quorum of 4, 'defer' basically means not voting, and this would have all kinds of implications for how you take average (if juror A is particularly harsh, this has more weight for the deferred picture, etc)
• If we have a quorum of more than 4, we could throw back the image into the pool and assign it randomly to a juror that has not been assigned this picture yet (e.g. juror A). But what if that juror was already finished? What if juror A then also defers? I don't think this is feasible.

Casting a blank ballot seems the only viable option, if you really want to support this intention. The risk is that it may harm some assumptions (when calculating the average, you don't want to divide over 0 etc) but may be the least harmful.

I would also be totally fine with not implementing this at all, and sticking with the assumption that all jurors will judge all photos assigned to them.