Import vehicle data in GTFS Realtime

[jamespfennell]

• Remove relevant columns from the Trip table.
• Add a new Vehicle table with all of the data.
• Add a nullable foreign key reference in Trip to Vehicle.
• Add parse types and a VehicleImporter to import vehicle data.
• Figure out how to mark appropriate StopTimes in the past, given the vehicle data. May just issue a query "update trip_stop_time set future = false where trip_pk = "...
• Adjust the HTTP API accordingly.

[jamespfennell]

Part 2

• Remove the not null constraint on vehicle ID
• Move the one-to-one linking column to the vehicle table
• Make the system_pk column optional. Perhaps trip_pk or system_pk must be provided. If the trip_pk column is not provided, a vehicle ID must be.
• During import, match existing vehicles using both the trip ID or, if there's no trip ID, the non-null vehicle ID.
• Add vehicle data to the following endpoints:
  • stops/<stop_id> - in the trip
  • routes/<route_id>/trips/ - in the trip
  • routes/<route_id>/trips/<trip_id> - in the trip
  • routes/<route_id>/trips/<trip_id>/vehicle - in the trip

[jamespfennell]

We need to have a "no overwrite" rule for vehicles. If the vehicle update is missing, then adding data from any encountered vehicle descriptor should not blow away data on the vehicle update