Guide: Passport auth example

Credit: @theangryangel

I'm not sure if this is of interest, but I've been fiddling with sails for the first time tonight - in particular I was fiddling with adding passport into the mix

The gist is a 20 minute PoC and totally shouldn't be used in production in this manner, but might be a good starting gist for someone else and might be useful as a companion to the Login Example wiki page.

https://gist.github.com/theangryangel/5060446