Create manual, selective group task sharing hook.

Check if it doesn't already exist first.

Suppose I planned a course, I might want to share this planning with my fellow taskwarrior users, without sharing other (private) tasks. Make a command/script that allows one to export all the tasks from pending.data that are for example selected with command: task share proj:uni.SomeCourse.

That should make a file containing the pending.data lines of those tasks, that is read by the task import filename.data command those tasks to the other users taskwarrior if she/he decides to import them.

Preferably by generating task objects that are turned into task add.. commands, so that the backlog.data and undo.data are also correct. Otherwise just copy the lines into pending.data.