RubyMoney/google_currency — pull request #21 by cover (2013-10-09 21:12:33+00:00)
Title: Permit to automatically expire rates after a given amount of seconds

One think that I miss is the ability to automatically flush rates, especially when running on background jobs or webservers that aren't restarted frequently, with the risk of using days old rates. I've added this to permit to automatically expire all the rates after a given amount of seconds. I hope you find it useful too :)