Add _index to named collection routes for uncountable resources (e.g. Sheep)

Signed-off-by: Rizwan Reza <rizwanreza@gmail.com>

actionpack/lib/action_dispatch/routing/mapper.rb

@@ -426,7 +426,11 @@ module ActionDispatch
           end
 
           def collection_name
-            plural
+            uncountable? ? "#{plural}_index" : plural
+          end
+          
+          def uncountable?
+            singular == plural
           end
 
           def name_for_action(action)

actionpack/test/dispatch/routing_test.rb

@@ -113,6 +113,8 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
       resources :posts, :only => [:index, :show] do
         resources :comments, :except => :destroy
       end
+      
+      resources :sheep
 
       match 'sprockets.js' => ::TestRoutingMapper::SprocketsApp
 
@@ -530,6 +532,13 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
       assert_raise(ActionController::RoutingError) { delete '/posts/1/comments' }
     end
   end
+  
+  def test_resources_for_uncountable_names
+    with_test_routes do
+      assert_equal '/sheep', sheep_index_path
+      assert_equal '/sheep/1', sheep_path(1)
+    end
+  end
 
   def test_path_names
     with_test_routes do