Add support for xing (#162)

_data/data.yml

@@ -16,6 +16,7 @@ sidebar:
     phone: 012 345 6789
     website: blog.webjeda.com #do not add http://
     linkedin: alandoe
+    xing: alandoe
     github: sharu725
     telegram: # add your nickname without '@' sign
     gitlab:

_includes/contact.html

@@ -31,6 +31,12 @@
     </li>
     {% endif %}
 
+    {% if sidebar.xing %}
+    <li class="xing"><i class="fab fa-xing"></i>
+      <a href="https://www.xing.com/profile/{{ sidebar.xing }}" target="_blank">{{ sidebar.xing }}</a>
+    </li>
+    {% endif %}
+
     {% if sidebar.github %}
     <li class="github"><i class="fab fa-github"></i>
       <a href="http://github.com/{{ sidebar.github }}" target="_blank">{{ sidebar.github }}</a>