delete an unnecessary line
before_action assign_target_user for the destory and update method, and checking if carrent_user is not target_user.
replace not_admin? method to unless member.configurable?, so delete not_admin? method
delete an unnecessary line
replace first to take, and update_attributes to update_attributes\!
delete %div, replace remove_member to list_member div, change name of the div admin_member to grant_admin
replace put to patch
replace PUT to PATCH
delete describe for not_admin method
delete redirect where it is not actually redirect
delete unnecessary flash[:email] and flash[:error]
replace expect(subject.status).to eq(400) to it { is_expected.to be_bad_request }
replace should to is_expected.to