27: Create PlayerGroups persister
http://github.com/yoadsn/TonguesPlugin/issues/issue/27
28: Player Groups are loaded on server start from the file
"groupsStore.json"
http://github.com/yoadsn/TonguesPlugin/issues/issue/28
OPEN - task 29: Enable sending of chat messages to groups 
http://github.com/yoadsn/TonguesPlugin/issues/issue/29
Merge https://github.com/yoadsn/TonguesPlugin