Yup, they are adding new map: the proving grounds. That's this map that's in traning and you play ashe. There are two things you have to know about it:
-You start with 1375 gold, you exp rises automaticly and gold rises faster(like in dominion)
-When you'll come out of base, you can't go back for items (recall is disabled and shop after you leave the base).
I know this things, because I play daily on PBE server on this map
5vs5 on this map is carnage xd