add show_related option

_config.yml

@@ -7,6 +7,7 @@ date_format: "%B %d, %Y"
 
 sidebar: true                # show a sidebar instead of the usual header
 show_excerpts: false         # show article excerpts on the home page
+show_related: true           # show the previous and next links after every post
 dark_header: false           # keep the top-header dark
 hide_title: false            # hide the site title in the header
 minimal: false               # minima-inspired style without box-shadows

_includes/post.html

@@ -12,6 +12,15 @@ <h1><a href="{{ include.post.url | relative_url }}">{{ include.post.title }}</a>
     <div><a href="{{ include.post.url | relative_url }}">read more</a></div>
   {% else %}
     {{ include.post.content }}
+    {% if site.show_related %}
+      <p class="separator">Related posts</p>
+      {% if include.post.next.url %}
+        <p class="related"><span>Next Post</span><a href="{{ include.post.next.url | relative_url }}">{{ include.post.next.title }}</a></p>
+      {% endif %}
+      {% if include.post.previous.url %}
+        <p class="related"><span>Previous Post</span><a href="{{ include.post.previous.url | relative_url }}">{{ include.post.previous.title }}</a></p>
+      {% endif %}
+    {% endif %}
     {% if include.post.comments != false and site.comments.isso or site.comments.disqus %}
       <hr>
       {% if site.comments.isso %}<div id="isso-thread"></div>{% endif %}

assets/css/classes.sass

@@ -9,6 +9,31 @@
 .categories + h1
   margin: .1em 0
 
+{% if site.show_related %}
+
+.separator
+  display: flex
+  color: reduce(100)
+  margin: 2em -.8em
+
+.separator::before, .separator::after
+  display: block
+  content: " "
+  margin: .8em
+  border-top: 1px solid reduce(26)
+  flex: 1
+
+.related span
+  display: block
+  color: reduce(100)
+
+.related a
+  color: inherit
+  font-size: 1.2em
+  font-weight: bold
+
+{% endif %}
+
 {% if site.sidebar %}
 
 .hidden