title: Phoenix: Use layout with templates of formats differents from html
body: <p>I have the default <code>app.html.eex</code> in <code>web/templates/layout/</code> and it works well with all my templates <code>*.html.eex</code>. I duplicated the <code>app.html.eex</code> file to <code>app.rss.eex</code> and I changed the content to the common RSS code to use in my <code>*.rss.eex</code> templates only the specific code, but it only renderize the <code>*.rss.eex</code> code and not to use the layout.</p>
  
  <p>I tried to put in the pipeline <code>plug :put_layout, {Exampleapp.LayoutView, :app}</code> but it didn't work. Of course, I configured the accepts to use RSS with <code>plug :accepts, ["html", "rss"]</code> so that it can render <code>*.rss.eex</code> templates.</p>
  
  <p>¿Is possible to use the layout with other formats?
  ¿How can I use the layout with <code>app.rss.eex</code> correctly?</p>