Install Firefox 3.6 alpha1pre Minefield in Ubuntu (from repository)

You may ask why would you want to install Firefox 3.6 alpha1pre Minefield in Ubuntu. Well, for testing purposes of course. While it worked ok for me in the 10 minutes browsing i used it, being in it's early alpha stages it should only be used for testing addons and to see the way web pages are rendered.

Below I will explain how to install Firefox 3.6 alpha from the repositories, in Ubuntu: