Gmail Notifications Missing? Check your system settings

After updating to Android 2.2 and the newest version of the Gmail app, I recently noticed that the app was no longer notifying me of new messages.  Any time I would open the Gmail app I had to manually check for new mail.  Doing a quick search on the internet resulted in zero hits with an answer to what happened.  After doing some digging I managed to find the root of the cause.  The most logical place to start was the app settings.  Clear as day in the setting you will see a check box for "Email Notifications", but in my case this was already checked.  So it was time to dig a little deeper.  Being an android phone it's already linked to my Gmail account, but why would that affect the app?  After a long search in the phone settings I came across something I had never really payed attention to before.  In the "Accounts and Sync" menu is the "Auto-Sync" selection, in my case this was turned off for some reason.  Sure enough after turning the Auto-Sync setting back on the Gmail app started chiming in when new mail arrived.  What caused this to happen is hard to say.  Could it have been a glitch in one of the updates, or some rouge app, I may never know.  But in case you find yourself in the same boat as I was, you will find the steps to fix it below.