fix collection_radio_buttons elem name
fix collection_radio_buttons elem name

Since we're creating radio buttons, the element name should not end
with '[]' because that will cause Rails and other frameworks to parse
that value into an array eventhough the browser will only let the user
select one option.

18Months/bootstrap_forms,18Months/bootstrap_forms,sshaw/padrino_bootstrap_forms,sethvargo/bootstrap_forms,sethvargo/bootstrap_forms