Updated PaymentMethods to register correctly

lib/spree_paypal_express.rb

@@ -7,16 +7,17 @@ module SpreePaypalExpress
     config.autoload_paths += %W(#{config.root}/lib)
 
     def self.activate
-      #workaround for https://github.com/Shopify/active_merchant/issuesearch?state=open&q=paypal#issue/43
-      require 'active_merchant'
-      ActiveMerchant::Billing::PaypalExpressGateway
-
+      debugger
       Dir.glob(File.join(File.dirname(__FILE__), "../app/**/*_decorator*.rb")) do |c|
         Rails.env.production? ? require(c) : load(c)
       end
+    end
 
-      BillingIntegration::PaypalExpress.register
-      BillingIntegration::PaypalExpressUk.register
+    initializer "spree_paypal_express.register.payment_methods" do |app|
+      app.config.spree.payment_methods += [
+        BillingIntegration::PaypalExpress,
+        BillingIntegration::PaypalExpressUk
+      ]
     end
 
     config.to_prepare &method(:activate).to_proc