Added a missing (but required) parameter for programmatically registering users

WePay does not enforce the requiredness of this parameter in its staging environment, but it does in production so we need a way to set the value.
No worries at all... just pointing it out. =) Btw, Intellij is *well* worth the money. I've switched now to that being my editor and I'm in love with it. Not just for Java, but html, css, coffeescript, js, etc...