Add social sharing buttons

_includes/sharing.html

@@ -0,0 +1,29 @@
+<div id="fb-root"></div>
+  <script>(function(d, s, id) {
+    var js, fjs = d.getElementsByTagName(s)[0];
+    if (d.getElementById(id)) return;
+    js = d.createElement(s); js.id = id;
+    js.src = "//connect.facebook.net/en_US/all.js#xfbml=1&appId=YOUR_APP_ID";
+    fjs.parentNode.insertBefore(js, fjs);
+    }(document, 'script', 'facebook-jssdk'));
+  </script>
+
+  <script type="text/javascript">
+    (function(){
+     var twitterWidgets = document.createElement('script');
+     twitterWidgets.type = 'text/javascript';
+     twitterWidgets.async = true;
+     twitterWidgets.src = 'http://platform.twitter.com/widgets.js';
+     document.getElementsByTagName('head')[0].appendChild(twitterWidgets);
+     })();
+  </script>
+
+  <script type="text/javascript">
+    (function() {
+      var po = document.createElement('script');
+      po.type = 'text/javascript'; po.async = true;
+      po.src = 'https://apis.google.com/js/plusone.js';
+      var s = document.getElementsByTagName('script')[0];
+      s.parentNode.insertBefore(po, s);
+    })();
+  </script>

_includes/themes/twitter/post.html

@@ -27,6 +27,8 @@ <h1>{{ page.title }} {% if page.tagline %}<small>{{page.tagline}}</small>{% endi
     </ul>
   {% endunless %}  
 
+  {{ page.url | share_buttons }}
+
     <hr>
     <div class="pagination">
       <ul>

_plugins/share_buttons.rb

@@ -0,0 +1,35 @@
+  module Jekyll
+    module ShareButtonsFilter
+      def share_buttons url
+        full_url = @context.registers[:site].config['production_url'] + url
+
+        <<-HTML
+          <div class="buttons">
+            <div class="fb-like"
+              data-href="#{full_url}"
+              data-send="true"
+              data-layout="button_count"
+              data-width="90"
+              data-show-faces="false">
+            </div>
+
+            <a href="https://twitter.com/share"
+              class="twitter-share-button"
+              data-url="#{full_url}"
+              data-lang="en">
+            </a>
+
+            <div class="google_plus">
+              <div class="g-plusone"
+                data-href="#{full_url}"
+                data-size="medium"
+                data-annotation="bubble">
+              </div>
+            </div>
+          </div>
+        HTML
+      end
+    end
+  end
+
+  Liquid::Template.register_filter Jekyll::ShareButtonsFilter

assets/themes/twitter/css/style.css

@@ -35,6 +35,20 @@ body {
   margin-bottom: 12px;
 }
 
+.buttons {
+  margin: 30px 0 20px 30px;
+}
+
+.fb-like {
+  display: inline;
+  margin: 0 30px 0 0;
+  bottom: 6px;
+}
+
+.google_plus {
+  display: inline;
+}
+
 /* Custom container */
 .container-narrow {
   margin: 0 auto;