Accepts G+ username instead of full URL, adds Google authorship as per https://support.google.com/webmasters/answer/1408986?expand=option2

Author: maxheld83

_includes/_author-bio.html

@@ -3,7 +3,8 @@ <h3>{{ site.owner.name }}</h3>
 <p>{{ site.owner.bio }}</p>
 {% if site.owner.twitter %}<a href="http://twitter.com/{{ site.owner.twitter }}" class="author-social" target="_blank"><i class="icon-twitter"></i> Twitter</a>{% endif %}
 {% if site.owner.facebook %}<a href="http://facebook.com/{{ site.owner.facebook }}" class="author-social" target="_blank"><i class="icon-facebook"></i> Facebook</a>{% endif %}
-{% if site.owner.google_plus %}<a href="{{ site.owner.google_plus }}" class="author-social" target="_blank"><i class="icon-google-plus"></i> Google+</a>{% endif %}
+{% if site.owner.google_plus %}<a href="http://plus.google.com/+{{ site.owner.google_plus }}?
+   rel=author" class="author-social" target="_blank"><i class="icon-google-plus"></i> Google+</a>{% endif %}
 {% if site.owner.linkedin %}<a href="http://linkedin.com/in/{{ site.owner.linkedin }}" class="author-social" target="_blank"><i class="icon-linkedin"></i> LinkedIn</a>{% endif %}
 {% if site.owner.instagram %}<a href="http://instagram.com/{{ site.owner.instagram }}" class="author-social" target="_blank"><i class="icon-instagram"></i> Instagram</a>{% endif %}
 {% if site.owner.tumblr %}<a href="http://{{ site.owner.tumblr }}.tumblr.com" class="author-social" target="_blank"><i class="icon-tumblr"></i> Tumblr</a>{% endif %}