Adding ability to automatically calculate the total_cost value for gasoline mileage.
Updating the models to provide default values.
Adding payment model to the application.
No idea
Added payment types to the model.  Starting to put in the URLs.  Still have some work to do before can start testing the new functionality.
Adding ability to list the payment records in the car detail, and adding them to the total cost calculations.
Cleaning up the form display for payments.
Fixed the type string in the table on car details.
Fixing the overriding datetimes when editing records.