Author: Shamim Rezaie
MDL-61114 mod_assign: assignment overrides to observe group membership
http://git.moodle.org/gw?p=moodle.git;a=commit;h=9cb135db20b63bf445da91fcf2de2fbf3194d738
http://github.com/moodle/moodle/commit/9cb135db20b63bf445da91fcf2de2fbf3194d738
+ 3.8 en [groupsnone,mod_assign]