Shopify/active_merchant — pull request #589 by duff (2013-02-16 21:15:26+00:00)
Title: First Data E4: Add credential instructions

Added a comment so users of the API know what credentials they need to
use and where to find those credentials.

Figuring out the right credentials can be painful with E4 since they cut
you off for 15 minutes if you get it wrong a few times. Hopefully these
instructions will save folks some time.