To install Astade in Debian add the following lines to your /etc/apt/sources.list (resp. the sources.list.d/astade.list):
deb http://ppa.launchpad.net/astade/daily/ubuntu/ devel main deb-src http://ppa.launchpad.net/astade/daily/ubuntu/ devel main
Afterwards you can run (as usual):
apt-get update apt-get install astade
Voila.