Added "New event" button to calendar view

Author: jasonjoh

demo/graph-tutorial/views/calendar.hbs

@@ -2,7 +2,8 @@
      Licensed under the MIT License. -->
 
 <!-- <LayoutSnippet> -->
-<h1>Calendar</h1>
+<h1 class="mb-3">Calendar</h1>
+<a href="/calendar/new" class="btn btn-light btn-sm mb-3">New event</a>
 <table class="table">
   <thead>
     <tr>