So Play 2.1 is officialy out and one of the new features it brings is the ability to configure root application context. It have been in 2.1 branch for a long-long time and I don't see this mentioned in highlights section, but nevertheless it's there and it works.
To assign a root context to your play app just open your
application.conf file and add the following line
Make sure you have it starting with slash (
/) otherwise play will throw a configuration error at you saying "Invalid application context".