Author: Shamim Rezaie
MDL-62318 core_group: Add implementation of privacy API
http://git.moodle.org/gw?p=moodle.git;a=commit;h=55c1865638eba1e2620b2a79e961064c8cf3ec14
http://github.com/moodle/moodle/commit/55c1865638eba1e2620b2a79e961064c8cf3ec14
+ 3.5 en [privacy:metadata:groups,core_group]
+ 3.5 en [privacy:metadata:groups:groupid,core_group]
+ 3.5 en [privacy:metadata:groups:timeadded,core_group]
+ 3.5 en [privacy:metadata:groups:userid,core_group]