Switched CSS framework to Bootstrap

views/index.twig

@@ -5,7 +5,7 @@
 {% block content %}
 
   <div class="row">
-    <div class="twelve columns">
+    <div class="col-12">
       <h1>Welcome to Colossus!</h1>
       <p>Using Colossus, you can easily organize your hardware benchmark results.</p>
     </div>
@@ -14,7 +14,7 @@
   <hr>
 
   <div class="row">
-    <div class="twelve columns">
+    <div class="col-12">
       <p><a href="{{ url_for('test.list') }}">View current tests</a></p>
       <p><a href="{{ url_for('test.add') }}">Add a new test</a></p>
     </div>