By adding Appalachian State (who is Hot!Hot!Hot!) and Georgia Southern. That is great news for about 2/3 of the SEC, since those games will now be D1-A contest in counting towards bowls/whatever metric the new college football overlords decided to use in assessing what wins are good in making decisions about a bunch of 10-2 teams. They will both join in 2015.
Georgia Southern has been a staple on Georgia's Schedule, appearing three times in Coach Richt's tenure, the most recent being last fall. They will be a Sun Belt team when they come to Athens in Fall 2016. App State will be in Athens this fall on September 7th.
No word on if Georgia Gulf Coast University will move from the ACC yet.