app/views/comments/_form.html.erb
<%= form_for([@post, @comment], html: { class: 'form-vertical' }) do |f| %>
<% if @comment.errors.any? %>
<div class="alert alert-error">
<h2><%= t('activerecord.errors.template.header', model: Comment.model_name.human, count: @comment.errors.count) %></h2>
<ul>
<% @comment.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="control-group">
<%= f.label :author, class: 'control-label' %>
<div class="controls">
<%= f.text_field :author, required: true, placeholder: t('name') %>
</div>
</div>
<div class="control-group">
<%= f.label :body, class: 'control-label' %>
<div class="controls">
<%= f.text_area :body, required: true, class: 'span6', placeholder: t('markdown') %>
</div>
</div>
<div class="control-group">
<div class="controls">
<%= f.submit class: 'btn btn-primary' %>
</div>
</div>
<% end %>