This little bit of "translation" between what we might receive as input and what ActiveMerchant requires is important, but currently the responsibility for this job is spread all over the code base. It can now just live in the CreditCard model (in one place) and doesn't need to be duplicated anywhere else (like several different places in frontend Javascript!)
Add paymentMethodsAPI specific mapping function, we had some errors in production with mastercards probably caused by ActiveMerchant not handling the card type correctly
