event.rb

Superclass for anything that can have results:

• Event (Superclass only used to organizes multiple sets of results on a single day.

         Examples: Alpenrose Challenge Morning Session, Alpenrose Challenge Afternoon Session)
  

• SingleDayEvent (Most events, an event on a particular date. Appears on calendar.)
• MultiDayEvent (Spans more than one day. has many SingleDayEvent children)
• Competition (Results are calculated/derived from other events’ results. Examples: Combined TT times, OBRA BAR)

instructional: class or clinc practice: training session

Events have four similar, but distinct relationships to other Events:

• parent-children: A one-to-many tree. Example: stage race parent + stages children. Used for calculating competition results and schedule display. Does not include Competitions, even though Competitions can have Event parents.

  A purer children association would return all child Events and Competitions

 (that's how they are in the database). But we almost always want just the child Events,
  and not the Competitions.

• parent-child_competitions: A one-to-many tree. Example: stage race MultiDayEvent parent with GC and KOM child_competitions. Typically combined with children when we really do want all child Competitions and Events.
• competition_event_memberships: many-to-many from Events to Competitions. Example: Banana Belt I can be a member of the Oregon Cup and the OBRA Road BAR. And the Oregon Cup also includes Kings Valley RR, Table Rock RR, etc. CompetitionEventMembership is a meaningul class in its own right.

Changes to parent Event‘s attributes are propogated to children, unless the children‘s attributes are already different. See PROPOGATED_ATTRIBUTES

It‘s debatable whether we need STI subclasses or not.

All notification code just supports combined TT results, and should be moved to background processing