Added default auth level for newly added users in a group

src/main/java/ntnu/idatt2016/v233/SmartMat/controller/group/GroupController.java

@@ -283,6 +283,7 @@ public class GroupController {
                 .id(userGroupId)
                 .group(group)
                 .user(user)
+                .groupAuthority("USER")
                 .build();
 
         user.addGroup(userGroupAsso);