Add /post_replacements.json, /posts/1234/replacements.json.

config/routes.rb

@@ -199,6 +199,7 @@ Rails.application.routes.draw do
   end
   resources :posts do
     resources :events, :only => [:index], :controller => "post_events"
+    resources :replacements, :only => [:index], :controller => "post_replacements"
     resource :artist_commentary, :only => [:index, :show] do
       collection { put :create_or_update }
       member { put :revert }
@@ -217,6 +218,7 @@ Rails.application.routes.draw do
   end
   resources :post_appeals
   resources :post_flags
+  resources :post_replacements, :only => [:index]
   resources :post_versions, :only => [:index, :search] do
     member do
       put :undo