Bootstrap _form validation

_form.html.erb

<%= simple_form_for @record, :html => { :class => 'form-horizontal' } do |f| %>
  <fieldset>
    <legend><%= controller.action_name.capitalize %></legend>
    <%= f.input :title %>
    <%= f.input :amount %>
    <%= f.association :category %>
    <%= f.input :date %>
    
    <div class="form-actions">
      <%= f.submit nil, :class => 'btn btn-primary' %>
      <%= link_to t('.cancel', :default => t("helpers.links.cancel")),
                  records_path, :class => 'btn' %>
    </div>
  </fieldset>
<% end %>