gistfile1.rb

def join_link
    return if @appointment.full?
    return "#{link_to 'register', new_client_path} or #{link_to 'log in', '/login'} to join this class" if !current_user
    return 'Incorrect role, must be a client to sign up for a class' if !current_user.has_role?('client')
    return 'You are already signed up for this class' if current_user.appointments.include?(@appointment)
    link_to 'join class', add_client_to_appointment
  end