code: function addRolePrivilege (access, role, privilege) {
    if (role === true || access[privilege].role === true) {
      access[privilege] = {
        role: true
      }
      return
    }
  
    access[privilege].role = _.union(access[privilege].role, _.concat(role))
  }
docs: If setting privilege to true (everyone has access) or
  if the current setting already is true, then set the privilege to true.
  Otherwise merge the current and added roles to an array, avoiding duplicates.