Add "watch video on YouTube link"

src/invidious/views/watch.ecr

@@ -334,6 +334,7 @@ get_youtube_comments();
 <div class="pure-g">
     <div class="pure-u-1 pure-u-md-1-5">
         <div class="h-box">
+            <p><a href="https://www.youtube.com/watch?v=<%= video.id %>">Watch video on YouTube</a></p>
             <p><i class="icon ion-ios-eye"></i> <%= number_with_separator(video.views) %></p>
             <p><i class="icon ion-ios-thumbs-up"></i> <%= number_with_separator(video.likes) %></p>
             <p><i class="icon ion-ios-thumbs-down"></i> <%= number_with_separator(video.dislikes) %></p>