Fix centering of podcast cover image

app/templates/podcasts/show.hbs

@@ -3,7 +3,7 @@
     <h1 class="ui header">{{model.title}}</h1>
   </div>
 
-  <div class="seven wide column centered podcast-cover">
+  <div class="fourteen wide column centered center aligned podcast-cover">
     <img src={{model.coverImageURL}} alt={{model.title}}>
   </div>