I'll eventually try it out, but I have absolutely no idea how to go from this .war file to a running web server. (I see some .war files actually have a web server built in so you can just to java -jar, but not this one.)
I haven't tried installing it yet, but in principle installing .war files can be very simple. You need an application server (such as Apache Tomcat), you log into the admin section of that in your browser, and somewhere in there there's a form where you just upload the .war file, and it gets automatically unpacked, installed, services started up, and so on.
Edit: I take it all back. Well, most of it. They have an install guide, which you can find via Support, Documentation.
Stupid Java environment. :-(
apt-get install tomcat7 tomcat7-admin; sudo $EDITOR /etc/tomcat7/tomcat-users.xml # add user with role manager-gui
Then I just went to http://localhost:8080/manager/ and uploaded the .war file. Et voilà.