Build navigation list include helper

- Update navigation.yml to support multiple navigations and levels
- Optional include navigation into left sidebar

_data/docs.yml

@@ -0,0 +1,56 @@
+- title: Getting Started
+  children:
+    - title: "Quick Start Guide"
+      path: quick-start-guide
+    - title: "Installation"
+      path: installation
+    - title: "Upgrading"
+      path: upgrading
+    - title: "Structure"
+      path: structure
+
+- title: Customization
+  children:
+    - title: "Configuration"
+      path: configuration
+    - title: "Navigation"
+      path: navigation
+    - title: "Authors"
+      path: authors
+    - title: "UI Text"
+      path: ui-text
+    - title: "Layouts"
+      path: layouts
+
+- title: Content
+  children:
+    - title: "Working with Posts"
+      path: working-with-posts
+    - title: "Working with Pages"
+      path: working-with-pages
+    - title: "Working with Collections"
+      path: working-with-collections
+    - title: "Jekyll Include Helpers"
+      path: include-helpers
+    - title: "Images"
+      path: images
+
+- title: Miscellaneous
+  children:
+    - title: "Pagination"
+      path: pagination
+    - title: "Archives"
+      path: archives
+    - title: "Development"
+      path: development
+    - title: "v2 Documentation"
+      path: docs-2
+
+- title: Meta
+  children:
+    - title: "Contributing"
+      path: contributing
+    - title: "License"
+      path: license
+    - title: "History"
+      path: history

_data/navigation.yml

@@ -1,5 +1,5 @@
-# Site navigation links
-
+# main links links
+main:
   - title: "Theme Setup"
     url: /theme-setup/
 
@@ -17,3 +17,63 @@
 
   - title: "Collections"
     url: /collection-archive/
+
+
+# documentation links
+docs:
+  - title: Getting Started
+    children:
+      - title: "Quick Start Guide"
+        path: quick-start-guide
+      - title: "Installation"
+        path: installation
+      - title: "Upgrading"
+        path: upgrading
+      - title: "Structure"
+        path: structure
+
+  - title: Customization
+    children:
+      - title: "Configuration"
+        path: configuration
+      - title: "Navigation"
+        path: navigation
+      - title: "Authors"
+        path: authors
+      - title: "UI Text"
+        path: ui-text
+      - title: "Layouts"
+        path: layouts
+
+  - title: Content
+    children:
+      - title: "Working with Posts"
+        path: working-with-posts
+      - title: "Working with Pages"
+        path: working-with-pages
+      - title: "Working with Collections"
+        path: working-with-collections
+      - title: "Jekyll Include Helpers"
+        path: include-helpers
+      - title: "Images"
+        path: images
+
+  - title: Miscellaneous
+    children:
+      - title: "Pagination"
+        path: pagination
+      - title: "Archives"
+        path: archives
+      - title: "Development"
+        path: development
+      - title: "v2 Documentation"
+        path: docs-2
+
+  - title: Meta
+    children:
+      - title: "Contributing"
+        path: contributing
+      - title: "License"
+        path: license
+      - title: "History"
+        path: history

_includes/masthead.html

@@ -7,7 +7,7 @@
     <nav id="site-nav" class="greedy-nav">
       <button><div class="navicon"></div></button>
       <ul class="visible-links">
-        {% for link in site.data.navigation %}
+        {% for link in site.data.navigation.main %}
           {% if link.url contains 'http' %}
             {% assign domain = '' %}
             {% else %}

_includes/nav_list.html

@@ -0,0 +1,24 @@
+{% include base_path %}
+{% assign navigation = site.data.navigation[page.sidebar.nav] %}
+
+<nav>
+  <ul>
+    {% for nav in navigation %}
+      <li>{{ nav.title }}
+        {% if nav.children != null %}
+        <ul>
+          {% for child in nav.children %}
+            {% assign nav_url = child.path | prepend: "/" | prepend: page.sidebar.nav | prepend: "/" | append: "/" | prepend: base_path %}
+            {% if nav_url contains page.url %}
+              {% assign c = "current" %}
+            {% else %}
+              {% assign c = "" %}
+            {% endif %}
+            <li><a href="{{ nav_url }}" class="{{ c }}">{{ child.title }}</a></li>
+          {% endfor %}
+        </ul>
+        {% endif %}
+      </li>
+    {% endfor %}
+  </ul>
+</nav>

_includes/sidebar.html

@@ -15,6 +15,9 @@
       {% if s.title %}<h3>{{ s.title }}</h3>{% endif %}
       {% if s.text %}{{ s.text | markdownify }}{% endif %}
     {% endfor %}
+    {% if page.sidebar.nav %}
+      {% include nav_list.html items=page.sidebar.nav %}
+    {% endif %}
   {% endif %}
   </div>
 {% endif %}