def successful_authentication!(ip_address = nil)
      self.last_session_at = Time.now
      self.last_session_ip = ip_address if respond_to?(:last_session_ip=)
      self.save
      self.increment!(:session_count, 1)
    end
def successful_authentication!(ip_address = nil)
      self.last_session_at = Time.now
      self.last_session_ip = ip_address if respond_to?(:last_session_ip=)
      self.save
      self.increment!(:session_count, 1)
    end
Called when a +Session+ validation is successful, and this user has
 been authenticated.