Auto-allocate bibs at session start

Kids play sport with their friends. But equally, encouraging mixing helps build trust across the whole team. 

A common solution is to allocate bibs at the start of a session, but then too becomes a challenge to ensure sufficient mixing.

TeamsApp can assign bibs as players arrive, in a manner that keeps a balance to the groups and also to ensure optimal mixing between successive sessions.

Bib settings are carried forward when activities are duplicated.