add support for featured image

_layouts/post.html

@@ -15,6 +15,7 @@ layout: default
       </p>
 
     <h3 class="post-title p-name" itemprop="name headline">{{ page.title | escape }}</h3>
+    <img alt="{{ page.title }} | Developer Blog How To" title="{{page.image-attrib}}" src="../assets/images/{{page.image}}" />
   </header>
 
   <div class="post-content e-content" itemprop="articleBody">

_posts/2018-01-02-hello-world.md

@@ -1,6 +1,8 @@
 ---
 title: "Hello, World! A New Site for Dev Life Hacks!"
-permalink: '/hello-world'
+permalink: "/hello-world"
+image: "hello-world.jpg"
+image-attrib: "Photo stock by Lukas from Pexel."
 ---
 
 It's kind of getting old, I know.