validates_presence_of     :home_site, :unless => Proc.new { |u| u.superuser? }

##

  SUPERUSER = 1
  ADMIN     = 2
  MANAGER   = 3
  ATTENDANT = 4
  DEFAULT_ROLE = ATTENDANT
  ROLES = [ SUPERUSER, ADMIN, MANAGER,  ATTENDANT ]


##

  def superuser?
    role == SUPERUSER
  end