SUDO=$(which sudo) # We might not have a sudo
wget -qO - http://apt.webingenia.com/key.gpg | $SUDO apt-key add - # We add the key
echo "deb http://apt.webingenia.com/ unstable/" | $SUDO tee /etc/apt/sources.list.d/webingenia.list # And the repository
$SUDO apt-get update # And we update our repositories