Improve Group#users_with_parents method
Improve Group#users_with_parents method

Signed-off-by: Dmitriy Zaporozhets <be23d75b156792e5acab51b196a2deb155d35d6a@gmail.com>

t-zuehlsdorff/gitlabhq,openwide-java/gitlabhq,LUMC/gitlabhq,stoplightio/gitlabhq,dreampet/gitlab,dreampet/gitlab,dreampet/gitlab,axilleas/gitlabhq,stoplightio/gitlabhq,dplarson/gitlabhq,openwide-java/gitlabhq,mmkassem/gitlabhq,openwide-java/gitlabhq,stoplightio/gitlabhq,darkrasid/gitlabhq,darkrasid/gitlabhq,t-zuehlsdorff/gitlabhq,dplarson/gitlabhq,LUMC/gitlabhq,axilleas/gitlabhq,iiet/iiet-git,t-zuehlsdorff/gitlabhq,iiet/iiet-git,LUMC/gitlabhq,t-zuehlsdorff/gitlabhq,jirutka/gitlabhq,mmkassem/gitlabhq,dreampet/gitlab,axilleas/gitlabhq,darkrasid/gitlabhq,stoplightio/gitlabhq,iiet/iiet-git,openwide-java/gitlabhq,dplarson/gitlabhq,dplarson/gitlabhq,jirutka/gitlabhq,htve/GitlabForChinese,jirutka/gitlabhq,htve/GitlabForChinese,LUMC/gitlabhq,mmkassem/gitlabhq,axilleas/gitlabhq,htve/GitlabForChinese,iiet/iiet-git,jirutka/gitlabhq,htve/GitlabForChinese,mmkassem/gitlabhq,darkrasid/gitlabhq