Change rendering and fix minor bug

Change-Id: Ibc5f1b6785b71d18940f9e8868f8b4dbb2ba4e5f
diff --git a/person_detection/templates/index.html b/person_detection/templates/index.html
index 0cb83e7..4acf6d7 100644
--- a/person_detection/templates/index.html
+++ b/person_detection/templates/index.html
@@ -12,7 +12,7 @@
         </div>
         <div class="row">
           {% for x, y in devices.items() %}
-          <div class="col-6">
+          <div class="col-12">
             <div class="card">
               <img src="{{ url_for('video_feed', device=x) }}" class="card-img-top" alt="...">
               <div class="card-body">