Sort doc sections

_docs/config.md

@@ -3,6 +3,7 @@ toc:
     config:
         _title: Config
         url-rewriting: URL Rewriting
+nav: 4
 ---
 
 ## Config

_docs/creating_content.md

@@ -4,6 +4,7 @@ toc:
         _title: Creating Content
         text-file-markup: Text File Markup
         blogging: Blogging
+nav: 2
 ---
 
 ## Creating Content

_docs/install.md

@@ -5,6 +5,7 @@ toc:
         using-a-pre-bundled-release: Using a pre-bundled released
         composer: Composer
     run: Run
+nav: 1
 ---
 
 ## Install

_docs/upgrade.md

@@ -1,6 +1,7 @@
 ---
 toc:
     upgrade: Upgrade
+nav: 5
 ---
 
 ## Upgrade

docs.html

@@ -4,6 +4,7 @@ title: Docs
 nav: 2
 ---
 
+{% assign docs = site.docs|sort:"nav" %}
 <div class="light-wrapper">
     <div class="inner">
         <h1 class="aligncenter">Pico Documentation</h1>
@@ -14,7 +15,7 @@ nav: 2
 
         <div class="one-fourth">
             <ul>
-                {% for doc in site.docs %}
+                {% for doc in docs %}
                     {% for item in doc.toc %}
                         <li>
                             {% if item[1]._title %}
@@ -35,7 +36,7 @@ nav: 2
             </ul>
         </div>
         <div class="three-fourth last">
-            {% for doc in site.docs %}
+            {% for doc in docs %}
                 {{ doc.output }}
             {% endfor %}