Clubs -- data layer

[Levi-Lesches]

General implementation:

• Club dataclass holds everything about clubs
• User.registeredClubs holds user's clubs
• "Registering" means adding your User.contactInfo to the club's "members" sub-collection
• Registered members get notifications on events and meetings in the club
• Captains can create a club, but Dov has to approve it. Only then can others browse it
• Captains/faculty advisor take attendance every club meeting, is then cumulative
• Captains are recognized by Auth.customClaims ["clubs"] containing a club ID
• Dov has the scope AdminScope.clubs

Data

• List<String> User.registeredClubs
• Message
• Club (with a .fromJson)
• ContactInfo (with a .toJson)
• User.contactInfo
• User.toJson()