i have the follow

```
<%= form_tag lessons_path, :method => 'get', :name => "filter_form" do %>
  <div class="btn-group" data-toggle-name="is_private" data-toggle="buttons-radio" >
  <button value="0" class="btn" data-toggle="button">Public</button>
  <button value="1" class="btn" data-toggle="button">Private</button>
</div>

```

when a user clicks on either of those buttons, the form submits and goes to my lessons#index. how can i get what value the user clicked on? i understand that params[:something] usually comes from a GET request in the url, but what about in this case?

thanks