footer: add afterword

_layouts/default.html

@@ -48,6 +48,12 @@ <h4>{{ site.description | default: site.github.project_tagline }}</h4>
     </div>
 
     <footer class="container" style="padding-bottom: 1rem;">
+      {% if page.url contains "/articles/" or page.url contains "/algorithms/" %}
+      <p>
+        Afterword: QuanticDev is a website where I publish about software engineering. If you want to see future updates, follow me on <a href="https://www.youtube.com/quanticdev">youtube.com/quanticdev</a> or <a href="https://twitter.com/quantic_dev">twitter.com/quantic_dev</a>
+      </p>
+      {% endif %}
+
       <small>
         <a href="/about">About & Contact</a> · <a href="/privacy">Terms & Privacy</a> · MIT License
       </small>