app/views/manifestations/_youtube.html.erb
<tr>
<td style="width: 200px"><%= t('page.video') -%>:</td>
<td style="width: 500px">
<iframe width="425" height="355" src="https://www.youtube.com/embed/<%= manifestation.youtube_id %>?rel=0" frameborder="0" gesture="media" allow="encrypted-media" allowfullscreen></iframe>
</td>
</tr>