Add automatic anchor symbols using anchorjs

_includes/anchorjs.html

@@ -0,0 +1,6 @@
+<script type="text/javascript">
+  anchors.options = {
+    placement: 'left',
+  };
+  anchors.add('article h2, article h3, article h4, article h5, article h6');
+</script>

_includes/head.html

@@ -22,4 +22,7 @@
 
   <!-- RSS -->
   <link rel="alternate" type="application/atom+xml" title="{{ site.title }}" href="{{ site.baseurl }}/atom.xml">
+
+  <!-- JS -->
+  <script src="https://cdnjs.cloudflare.com/ajax/libs/anchor-js/2.0.0/anchor.min.js"></script>
 </head>

_layouts/page.html

@@ -8,4 +8,5 @@ layout: default
 
   <hr>
   {% include disqus.html %}
+  {% include anchorjs.html %}
 </article>

_layouts/post.html

@@ -19,4 +19,5 @@ layout: default
 
   <hr>
   {% include disqus.html %}
+  {% include anchorjs.html %}
 </article>

_sass/_base.scss

@@ -47,6 +47,10 @@ a {
   }
 }
 
+a.anchorjs-link:hover {
+    text-decoration: none;
+}
+
 img {
   display: block;
   max-width: 100%;