v0.3.2

• Add result_callback that allows to implement custom logic for Result URL.
• Fix README: describe the proper way how to call controller helpers within a callback.

@notification.success is moved from RobokassaController#paid, now callback is called there. To make this action return "OK#{ invoice_id }" again add config.result_callback = -> (controller, notification) { controller.render text: notification.success } line to your initializer.