##model
  def self.passwords_combine(password1,password2)
    unless (password1 == password2)
      return [nil, "Password's don't match"]
    end

    @hashed_password = hash_password(password1)
      return  [@hashed_password, nil]
  end

##controller
      @user.password, message = @user.passwords_combine(@user.password1, @user.password2)


##error
      undefined method `password1' for #<User:0x23860a0>