Change constructor signature for ActiveAdmin::Router (internal use on…

…ly).

lib/active_admin/application.rb

@@ -126,14 +126,18 @@ def files
       load_paths.flatten.compact.uniq.flat_map{ |path| Dir["#{path}/**/*.rb"] }
     end
 
-    def router
-      @router ||= Router.new(self)
-    end
-
-    # One-liner called by user's config/routes.rb file
+    # Creates all the necessary routes for the ActiveAdmin configurations
+    #
+    # Use this within the routes.rb file:
+    #
+    #   Application.routes.draw do |map|
+    #     ActiveAdmin.routes(self)
+    #   end
+    #
+    # @param rails_router [ActionDispatch::Routing::Mapper]
     def routes(rails_router)
       load!
-      router.apply(rails_router)
+      Router.new(router: rails_router, namespaces: namespaces).apply
     end
 
     # Adds before, around and after filters to all controllers.

lib/active_admin/router.rb

@@ -1,27 +1,21 @@
 module ActiveAdmin
+  # @private
   class Router
-    def initialize(application)
-      @application = application
+    attr_reader :namespaces, :router
+
+    def initialize(router:, namespaces:)
+      @router, @namespaces = router, namespaces
     end
 
-    # Creates all the necessary routes for the ActiveAdmin configurations
-    #
-    # Use this within the routes.rb file:
-    #
-    #   Application.routes.draw do |map|
-    #     ActiveAdmin.routes(self)
-    #   end
-    #
-    # @param router [ActionDispatch::Routing::Mapper]
-    def apply(router)
+    def apply(router = @router)
       define_root_routes(router)
       define_resources_routes(router)
     end
 
     private
 
     def define_root_routes(router)
-      @application.namespaces.each do |namespace|
+      namespaces.each do |namespace|
         if namespace.root?
           router.root namespace.root_to_options.merge(to: namespace.root_to)
         else
@@ -34,7 +28,7 @@ def define_root_routes(router)
 
     # Defines the routes for each resource
     def define_resources_routes(router)
-      resources = @application.namespaces.flat_map{ |n| n.resources.values }
+      resources = namespaces.flat_map{ |n| n.resources.values }
       resources.each do |config|
         define_resource_routes(router, config)
       end