wrangler

https://github.com/bmpercy/wrangler

A gem for handling exceptions thrown inside your Rails app. If you include the gem in your application controller, wrangler will render the error pages you configure for each exception or HTTP error code. It will also handle notifying you via email when certain exceptions are raised. Allows for configuration of which exceptions map to which error pages, which exceptions result in emails being sent. Also allows for asynchronous email sending via delayed job so that error pages don't take forever to load (but delayed_job is not required for sending email; wrangler will automatically send email synchronously if delayed_job is not available. . See README for lots of info on how to get started and what configuration options are available.