Assign sprockets static root

railties/lib/rails/application.rb

@@ -160,6 +160,7 @@ def build_asset_environment
 
       env = Sprockets::Environment.new(root.to_s)
       env.logger = Rails.logger
+      env.static_root = Rails.root.join("public/assets")
       env.ensure_fresh_assets = !config.action_controller.perform_caching
 
       self.class.default_sprockets_paths.each do |pattern|