Implementing new menu system in the docs site

content/tutorials/github_pages_blog.md

@@ -1,9 +1,11 @@
 ---
 title: "Hosting a Blog on GitHub Pages"
 date: "2014-03-21"
-groups: ["tutorials"]
-groups_weight: 10
+weight: 10
 author: "Spencer Lyon"
+menu:
+  main:
+    parent: 'tutorials'
 ---
 
 ## Intro

content/tutorials/mathjax.md

@@ -1,9 +1,11 @@
 ---
 title: "MathJax Support"
 date: "2014-03-20"
-groups: ["tutorials"]
-groups_weight: 10
+weight: 10
 author: "Spencer Lyon"
+menu:
+  main:
+    parent: 'tutorials'
 ---
 
 ## What is MathJax?

content/tutorials/migrate-from-jekyll.md

@@ -1,8 +1,10 @@
 ---
 title: "Migrate to Hugo from Jekyll"
 date: "2014-03-10"
-groups: ["tutorials"]
-groups_weight: 10
+weight: 10
+menu:
+  main:
+    parent: 'tutorials'
 ---
 
 ## Move static content to `static`