Ember.js - Where to put dropdown options?

I have a field in our DB that's a integer referring to a billing source. It can be 0, 1, 2, 3, or 4. This grew over time b/c originally was just 2 options. We have a Ruby class that handles this on the old frontend, something like this...

  module BillingSources
    Internal = 0
    Other = 1
    Other2 = 2
    Other3 = 3
  end

Where is the appropriate place to put the mapping of IDs to display in Ember.js?