#users.rb controller create method - restful_authentication

  def create
    logout_keeping_session!
    @user = User.new(params[:user])
    @amount = params[:plan][:amount].to_i
    @creditcard = ActiveMerchant::Billing::CreditCard.new(params[:creditcard])
    @creditcard.first_name = params[:creditcard][:firstname]
    @creditcard.last_name = params[:creditcard][:lastname]
    @subscription = Subscription.new
    @subscription = @subscription.process_card(@user, @creditcard, @amount)
    @user.register! if @user && @user.valid?
    success = @user && @user.valid?
    if success && @user.errors.empty?
      redirect_back_or_default('/')
      flash[:notice] = "Thanks for signing up!  We're sending you an email with your activation code."
    else
      flash[:error]  = "We couldn't set up that account, sorry.  Please try again, or contact an admin (link is above)."
      render :action => 'new'
    end
  end

#subscription.rb model

	# process the subscription - called from users controller on new
	def process_card(user, creditcard, amount)
		# create a new gateway object with credentials from development/production config
		gateway = ActiveMerchant::Billing::AuthorizeNetGateway.new(AUTHNET_CREDENTIALS)
		# has of keys and values required by the gateway to process the request
		options = {
	      :billing_address => {
	         :first_name => user.firstname,
	         :last_name => user.lastname,
	         :address1 => user.address,
	         :address2 => '',
	         :city     => user.city,
	         :state    => user.billing_state,
	         :country  => 'US',
	         :zip      => user.zip
	      },
	      :interval => { :length => 1, :unit => :months },
	      :duration => { :start_date => Date.today, :occurrences => 9999 }
	    }

	    # actually send the request
	    response = gateway.recurring(amount, creditcard, options)

		unless response.success?
			# saving responses even in the case of an error for troubleshooting more easily
			self.amount = amount
	      	self.message = response.message
	      	self.params = response.params.to_yaml
	      	self.save!
	      	error = "Credit card processing failed, try again."
	   	else
	      	# save the responses from the transaction in the subscription record
	      	self.user_id = user.id
	      	self.amount = amount
	      	self.message = response.message
	      	self.reference = response.authorization
	      	self.test = response.test?
	      	self.params = response.params.to_yaml
	      	self.user_id = user.id
	      	self.save!
	   end
	end
end