Update sidebar.html

web/_includes/sidebar.html

@@ -22,3 +22,11 @@ Follow @{{ site.twitter_username }}</a>
 <br>
 <div class="g-plusone" data-size="tall" data-annotation="inline" expandTo="right"></div>
 </div>
+<br>
+<hr>
+<br>
+<h3>Subscribe to our newsletter</h3>
+<form method="post" action="https://mail.gioxa.com/newsletter/subscribe/8c6b4ddb-c5d6-4124-8d67-296719748d1d">
+    <input name="subscriber" value="" placeholder="Enter your email address" />
+    <input type="submit" value="Subscribe" />
+</form>