app/views/pages/_getting_started_video_modal.html.erb
<div class="remodal video" data-remodal-id="getting-started-video">
<button data-remodal-action="close" class="remodal-close"><%= octicon 'x' %></button>
<div class="video-wrapper">
<iframe id="getting-started" width="100%" height="100%" src="https://www.youtube.com/embed/ChA_zph7aao?rel=0&showinfo=0&enablejsapi=1" frameborder="0" allowfullscreen></iframe>
</div>
</div>