Add Rails::Railtie.railtie_name method to allow setting custom name for railtie

actionpack/lib/action_dispatch/routing/mapper.rb

@@ -277,8 +277,13 @@ def default_url_options=(options)
         private
           def app_name(app)
             return unless app.respond_to?(:routes)
-            class_name = app.class.is_a?(Class) ? app.name : app.class.name
-            ActiveSupport::Inflector.underscore(class_name).gsub("/", "_")
+
+            if app.respond_to?(:railtie_name)
+              app.railtie_name
+            else
+              class_name = app.class.is_a?(Class) ? app.name : app.class.name
+              ActiveSupport::Inflector.underscore(class_name).gsub("/", "_")
+            end
           end
 
           def define_generate_prefix(app, name)

railties/lib/rails/plugin.rb

@@ -48,6 +48,10 @@ def self.all(list, paths)
 
     attr_reader :name, :path
 
+    def railtie_name
+      name.to_s
+    end
+
     def load_tasks
       super
       load_deprecated_tasks

railties/lib/rails/railtie.rb

@@ -164,8 +164,15 @@ def generators(&blk)
       def abstract_railtie?
         ABSTRACT_RAILTIES.include?(name)
       end
+
+      def railtie_name(name = nil)
+        @railtie_name = name if name
+        @railtie_name ||= ActiveSupport::Inflector.underscore(self.name).gsub("/", "_")
+      end
     end
 
+    delegate :railtie_name, :to => "self.class"
+
     def config
       @config ||= Railtie::Configuration.new
     end

railties/test/railties/engine_test.rb

@@ -28,6 +28,7 @@ def setup
         plugin.write "lib/bukkits.rb", <<-RUBY
           class Bukkits
             class Engine < ::Rails::Engine
+              railtie_name "bukkits"
             end
           end
         RUBY