Hydrant groups manager
Hydrant groups manager lives under /admin. Only users in the group admin_policy_object_editor can access this page. Groups are stored in config/role_mapper_[environment].xml
One can use RoleControls (lib/role_controls.rb) to add/remove groups or add/remove/mass assign users to a group. RoleControls uses RoleMapper from the hydra-access-controls gem.