production.rb

# Setup ActiveMerchant for production mode with Paypal Website Payments Pro
config.after_initialize do
  ActiveMerchant::Billing::Base.mode = :production
  ::GATEWAY = ActiveMerchant::Billing::PaypalGateway.new(
    :login => '[Add PayPal API login here]',
    :password => '[Add PayPal API password here]',
    :signature => '[Add PayPal API signature here]'
    )
end