This is a demo that utilizes the Mailboxer Ruby gem to provide private messaging functionality between users. I created this app to demonstrate Mailboxer functionality explained in a tutorial I wrote on my blog.
Create an account and send users a message. Feel free to create multiple accounts so you can test all of the features.
I wrote a tutorial that explains how to implement the mailboxer gem in your Rails app. Updated for Rails 4.2.
This app is completely open source and 100% free to use. The code is currently hosted on Github.