I implemented a Scalatra servlet and now want to create an executable jar, just like described in this tutorial: http://www.scalatra.org/2.2/guides/deployment/standalone.htm
For an up to date answer, please refer to these two files (Credits go to Scalatra in Action book):
https://github.com/scalatra/scalatra-in-action/blob/master/chapter09-standalone/src/main/scala/ScalatraLauncher.scala
and
https://github.com/scalatra/scalatra-in-action/blob/master/chapter09-standalone/project/Build.scala