public function serialize() {
      $data = array(
         'id' => $this->id,
         'userName' => $this->userName,
         'email' => $this->email,
         'password' => $this->password,
	 'name' => $this->name,
	 'firstName' => $this->firstName,
		    );
   }

   public function unserialize($serialized)
   {
     $data = unserialize($serialized);
     $this->id = $data['id'];
     $this->userName = $data['userName'];
     $this->email = $data['email'];
     $this->password = $data['password'];
     $this->name = $data['name'];
     $this->firstName = $data['firstName'];
   }