What is wrong with this code?

Hi. What is wrong with this code:
Do I have to create the button as a RoR special tag? how?

Hello!!! <%= start_form_tag :controller=>'greet', :action=>'say_hi' %>

Enter Your Name:

<%= @message %>

 <p>

    <%= submit_tag "Save" -%>

<%= end_form_tag %>

The submit_tag helper is what your after

http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html#M000502