Do not reload routes and make spree routes append instead of draw in

case thee routes are already defined elsewhere, for example, by the
paypal express gem

config/application.rb

@@ -33,12 +33,6 @@ class Application < Rails::Application
       end
     end
 
-    # We reload the routes here
-    #   so that the appended/prepended routes are available to the application.
-    config.after_initialize do
-      Rails.application.routes_reloader.reload!
-    end
-
     initializer "spree.environment", before: :load_config_initializers do |app|
       app.config.spree = Spree::Core::Environment.new
       Spree::Config = app.config.spree.preferences # legacy access

config/routes/spree.rb

@@ -1,5 +1,4 @@
-# Overriding Devise routes to use our own controller
-Spree::Core::Engine.routes.draw do
+Spree::Core::Engine.routes.append do
   devise_for :spree_user,
              :class_name => 'Spree::User',
              :controllers => { :sessions => 'spree/user_sessions',