The flyerhzm-bullet gem is designed to help you increase your application’s performance by reducing the number of queries it makes. It will watch your queries while you develop your application and notify you when you should add eager loading (N+1 queries) or when you’re using eager loading that isn’t necessary. It also provides some notification, such as javascript alert, browser console.log, bullet log, rails log and growl.

I think you will really like it.