Shopify/active_merchant — pull request #294 by brentmc79 (2012-03-06 14:53:03+00:00)
Title: Add option to retain payment methods once stored

Currently, if a credit card is stored with Samurai and there is no subsequent auth/payment, then the card is purged from their system within 24-48 hours. Using the new `:retain` option will request that Samurai retain the payment method for future use.

See the Samurai docs here: https://samurai.feefighters.com/developers/ruby/api-reference#retaining-a-payment-method