Add follow links to footer

- Close #205

_includes/footer

@@ -1,3 +1,5 @@
+{% include base_path %}
+
 {% if site.owner.google.ad-client and site.owner.google.ad-slot %}
 <div class="google-ads">
   <!-- 320 x 50 ad -->
@@ -12,4 +14,17 @@
 </div><!-- /.google-ads -->
 {% endif %}
 
-<span>&copy; {{ site.time | date: '%Y' }} {{ site.name | default: site.title }}. Powered by <a href="http://jekyllrb.com" rel="nofollow">Jekyll</a> using the <a href="https://mademistakes.com/work/minimal-mistakes-jekyll-theme/" rel="nofollow">Minimal Mistakes</a> theme.</span>
+<div class="follow">
+  <ul>
+    <li><strong>Follow:</strong></li>
+    {% if site.twitter.username %}
+      <li><a href="https://twitter.com/{{ site.twitter.username }}"><i class="fa fa-fw fa-twitter"></i> Twitter</a></li>
+    {% endif %}
+    {% if site.facebook.username %}
+      <li><a href="https://facebook.com/{{ site.facebook.username }}"><i class="fa fa-fw fa-facebook"></i> Facebook</a></li>
+    {% endif %}
+    <li><a href="{{ base_path }}/feed.xml"><i class="fa fa-fw fa-rss"></i> Feed</a></li>
+  </ul>
+</div>
+
+<div class="copyright">&copy; {{ site.time | date: '%Y' }} {{ site.name | default: site.title }}. Powered by <a href="http://jekyllrb.com" rel="nofollow">Jekyll</a> using the <a href="https://mademistakes.com/work/minimal-mistakes-jekyll-theme/" rel="nofollow">Minimal Mistakes</a> theme.</div>