Add leaderboard opt-in and Twitter button

www/index.html.spt

@@ -25,19 +25,23 @@ suppress_sidebar = True
 {% block content %}
 <h1>#BackTheStack</h1>
 
-<p>Free software isn't free. Do your part to fund it!</p>
-
-<p>Your company is built on free software. We help you fund it.</p>
-
-<p>Is your company built on free software? Fund it.</p>
+<p>Free software isn't free. Do your part to keep open source strong!</p>
 
 <ol>
     <li>Sign in with your company's Twitter account.</li>
     <li><a href="/about/me/emails/">Add and confirm</a> your billing email.</li>
     <li><a href="">Add a credit card</a>.</li>
     <li><a href="/search/">Search</a> or <a href="/explore/teams/">browse</a> for
         projects to fund.</li>
-    <li>Tell the world!</li>
+    <li><a href="">Opt-in to the leaderboard</a>.</li>
+    <li>Tell the world!
+        <a href="https://twitter.com/intent/tweet?button_hashtag=BackTheStack"
+           class="twitter-hashtag-button"
+           data-text="Free software isn&#39;t free. We #BackTheStack on @Gratipay! https://gratipay.com/"
+           data-show-count="false">Tweet #BackTheStack</a>
+    </li>
 </ol>
 
+<script async src="//platform.twitter.com/widgets.js" charset="utf-8"></script>
+
 {% endblock %}