app/views/notes/_form.html.erb
<%= form_for [@notable, note] do |f| %>
<%= error_messages_for note %>
<h4><%= note.notable_name %></h4>
<div class="field">
<%= f.label :content %><br>
<%= f.text_area :content, :cols => '80', :rows => '10', class: 'md_edit' %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>