Rails 4 routes always responds to :prepend

Author: amatsuda

lib/sprockets/railtie.rb

@@ -128,10 +128,8 @@ def configure(&block)
       Sprockets::Rails::Helper.raise_runtime_errors = app.config.assets.raise_runtime_errors
 
       if config.assets.compile
-        if app.routes.respond_to?(:prepend)
-          app.routes.prepend do
-            mount app.assets => config.assets.prefix
-          end
+        app.routes.prepend do
+          mount app.assets => config.assets.prefix
         end
       end
     end