Add sidebar links to u-view-templates

SIDEBAR.md

@@ -26,6 +26,8 @@ There's more to building RESTful web services than is covered here. You can cont
 
 * [REST][u-rest]
 * [JSON][u-json]
+* [View Templates][u-view-templates]
 
 [u-rest]: /understanding/REST
 [u-json]: /understanding/JSON
+[u-view-templates]: /understanding/view-templates