Habit tracking (add "DONE" state with configurable date/time)

[Angel de Vicente]

Hello,

I'm lately finding myself in this situation: I have a number of habits
that I track, and I want to mark one of them to "DONE", but registering
not the date when I change its state, but some other date/time (this
usually happens, for example, with my "sports" habit, which I do late at
night, so it is only next day when I turn on the computer that I can
change its state, but I want to register the state change date/time as
that of the previous day).

I thought that `C-u C-c C-t' might do this, but that apparently lets me
change the state but not the date.

Any ideas? Thanks
-- 
Ángel de Vicente
 Research Software Engineer (Supercomputing and BigData)
 Instituto de Astrofísica de Canarias (https://www.iac.es/en)