[spec] Add as helper to auth_helpers
[spec] Add more actions to controller_helpers
[factories] Add invalid_achievement factory
[factories] Rename admin to admin_user
[spec] Include handy_controller_helpers
[gem] Add handy_controller_helpers
[spec/controllers] Add admin/achievements_controller_spec
[spec] Fix auth_helpers
[admissions/spec] Refactor spec to use :as instead of :as_admin
[spec] Fix spec_helper
[spec] Clean auth_helpers
[core/spec] Refactor specs to use :as instead of :as_admin