Fixed bugs and made performance improvements:
- fixed one to many country -> city relation bug, as it was getting null navigation property
- re-configured data annotations in Airports.Models to establish correct and consistent object mapping
- configured all navigation properties to benefit from the EF lazy loading feature
- updated some constraints, declared as data annotations
- declared DbContentConsolePrinter static class to hold methods for basic database content visualization(used only for testing, and is to be deleted afterwards)
- made use of the Seed() method, re-written initial seed data
- deleted Location.cs as it was no longer needed
NOTE: After pulling the latest changes, you should probably need to delete your existing database(AirportsDb) and re-run the application.