Categorize time spent

Being able to tag time spent by area (was it dev, research, investigating, fix, whatever?) would help give more insight.

Add a ~label argument to /spend command or something to that effect.
Output should create a note saying something to the effect of:

Loic Nageleisen @lnageleisen added 30m of time spent on ~research at 2018-01-25 about 19 hours ago

Edited Jan 26, 2018 by Loic Nageleisen