Problems with select

[h0bit]

Hello to every body i have a problem when a user is going to sign up.

the problem is the next i have the next select on the view:

<p>
<%= f.label :es_pyme, I18n.t('tog_user.model.es_pyme') %>
<select name="user[es_pyme]" class="fieldbox">
<option value= "" >
<%= I18n.t("tog_user.model.select_type_of_user") %>
</option>
<option value= "Usuario" > Usuario </option>
<option value= "Pyme" > Pyme </option>
</select>
</p>

and in the migration of users a have a param which is
t.string :es_pyme

and the problems is that the select always retunr null instead of a
string.

Can anyone help me? thanks.