tweet link in downloads

source/downloads/index.html

@@ -94,6 +94,11 @@ platforms:
                 Password: 5iveL!fe
               </p>
             </div>
+            <div class="tab-step">
+              <p>Tweet about it!</p>
+              <a href="https://twitter.com/share" class="twitter-share-button" data-url="https://about.gitlab.com" data-text="I just installed Gitlab: open source software to collaborate on code. Check it out!" data-via="gitlabhq" data-size="large">Tweet about it!</a>
+              <script>!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+'://platform.twitter.com/widgets.js';fjs.parentNode.insertBefore(js,fjs);}}(document, 'script', 'twitter-wjs');</script>
+            </div>
             <div class="tab-step">
               <p>
                 For troubleshooting and configuration options please see the <a href="https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/README.md">Omnibus GitLab readme</a>