Skinny is a full-stack web app framework, which is built on Scalatra and additional components are integrated.
To put it simply, Skinny framework's concept is Scala on Rails. Skinny is highly inspired by Ruby on Rails and it is optimized for sustainable productivity for ordinary Servlet-based app development.
[Notice] Still in alpha stage. Architecture and API compatibility won't be kept until 1.0 release (2013 4Q).
See the website in detail.