This post is specific to installing the current stable (3.2.1) release of the Unifi controller software on Debian Wheezy.
Edit your sources.list file and add the following line.
deb http://www.ubnt.com/downloads/unifi/distros/deb/debian debian
Add the GPG key
sudo apt-key adv –keyserver keyserver.ubuntu.com –recv C0A52C50
Update your repos
sudo apt-get update
Install the v3 of Unifi
sudo apt-get install unifi-rapid
Note: If you already have v2 installed, you can simply remove unifi and then install unifi-rapid. That will upgrade your current config (at least it did for me).