The Rails 3 Beta got dropped a few days ago, and the release notes for Rails were put out a bit before that. The list of changes is long; this is a big release. There's a lot to sift through, a lot to change to upgrade your existing application, and a lot to learn whether you are upgrading or starting a new app. The big question is: WTF does all this mean to me? Don't worry, I'm going to tell you. If you want to read the full release notes, go f…