require 'money'
require 'money/bank/xe_currency'

# (optional)
# set the seconds after than the current rates are automatically expired
# by default, they never expire
Money::Bank::XeCurrency.ttl_in_seconds = 86400

# set default bank to instance of XeCurrency
Money.default_bank = Money::Bank::XeCurrency.new

# create a new money object, and use the standard #exchange_to method
money = Money.new(1_00, "USD") # amount is in cents
money.exchange_to(:EUR)

# or install and use the 'monetize' gem
require 'monetize'
money = 1.to_money(:USD)
money.exchange_to(:EUR)