Define proxy using `send` instead of `delegate`

Rails 4 will not delegate non-public methods

lib/draper/helper_proxy.rb

@@ -12,7 +12,7 @@ module Draper
 
     # Sends helper methods to the view context.
     def method_missing(method, *args, &block)
-      self.class.delegate method, to: :view_context
+      self.class.define_proxy method
       send(method, *args, &block)
     end
 
@@ -22,6 +22,12 @@ module Draper
 
     private
 
+    def self.define_proxy(name)
+      define_method name do |*args, &block|
+        view_context.send(name, *args, &block)
+      end
+    end
+
     def current_view_context
       ActiveSupport::Deprecation.warn("wrong number of arguments (0 for 1) passed to Draper::HelperProxy.new", caller[1..-1])
       Draper::ViewContext.current.view_context