Generates a migration to add a composite type called :money_with_currency to a Postgres database

Money implements a set of functions to store, retrieve and perform arithmetic on a %Money{} type that is composed of a currency code and a currency amount

Implements the Ecto.Type behaviour for a user-defined Postgres composite type called :money_with_currency

Implements Ecto.Type behaviour for Money, where the underlying schema type is a map

Implements functions to retrieve exchange rates from Open Exchange Rates

Default exchange rates retrieval callback module

Implements a GenServer to retrieve exchange rates from a configured retrieveal module on a periodic basis. By default exchange rates are retrieved from Open Exchange Rates