Adds ZipCode model and seeds database with zip codes & cities.
Updates models and associations to replace references to City with references to ZipCode
Seeds database with weather reports for NYC zip codes. Implements ZipCode methods to mirror those of City.
Starts duplicating views and controllers and replacing city references with zip code references.
Replaces city references with zip code references in entire app folder. Drops database.
Almost finishes transition from cities to zip codes.
Improves zip code show page. Adds chart to display condition percentages & star to toggle favorite. Adds routes to handle favorite toggle.