Use `ActiveSupport.on_load` to extend ActionController and ActionView.

http://api.rubyonrails.org/classes/ActiveSupport/LazyLoadHooks.html
92703a9ea5/actionpack/lib/action_controller/base.rb (L264)
7da8d76206/actionview/lib/action_view/base.rb (L215)

lib/rucaptcha.rb

@@ -35,5 +35,10 @@ module RuCaptcha
   end
 end
 
-ActionController::Base.send(:include, RuCaptcha::ControllerHelpers)
+ActiveSupport.on_load(:action_controller) do
-ActionView::Base.send(:include, RuCaptcha::ViewHelpers)
+  ActionController::Base.send :include, RuCaptcha::ControllerHelpers
+end
+
+ActiveSupport.on_load(:active_view) do
+  include RuCaptcha::ViewHelpers
+end