Draft schema for a Trip to model flights etc

[sunu]

How does this look? @brrttwrks @pudo @jlstro @Rosencrantz

Also, what do people think about adding a parent property to Event and Trip so that we can nest events and trips to represent a sequence of events as part of a larger event?

refs #616

[pudo]

Nice work! I wonder if using Address objects on this may be a better path, so that those can be browsed as objects and show their "trips incoming", "trips departing"?

[sunu]

Yes, that makes sense. I'll update the schema

[brrttwrks]

I definitely agree with using Address objects. If we are referencing, say, airports, that might be good to show which trips departed or arrived from that address. Also, agree with the parent property - I can definitely see use cases for it and it is a nice way to relate events to super-events or vice versa.