Switched to handlebars for templateing

ref #5

src/templates/sponsoring_contract.html

@@ -6,10 +6,10 @@
   </head>
   <body>
     <div class="page">
-      <p>ID: {{runner_id}}</p>
-      <p>FIRSTNAME: {{runner_firstname}}</p>
-      <p>LASTNAME: {{runner_lastname}}</p>
-      <p>GROUP: {{runner_groupname}}</p>
+      <p>ID: {{runner.id}}</p>
+      <p>FIRSTNAME: {{runner.firstname}}</p>
+      <p>LASTNAME: {{runner.lastname}}</p>
+      <p>GROUP: {{runner.group.name}}</p>
     </div>
   </body>
 </html>