Fixes #1408 - update link to Teach site

public/views/home-3.html

@@ -34,7 +34,7 @@
         <div class="col-sm-12 col-md-12 col-lg-12">
           <h3>{{ 'Want to teach the web to others?' | i18n }}</h3>
           <p>{{ 'Join Mozillas community of educators' | i18n }}</p>
-          <a class="btn" href="https://teach.mozilla.org">{{ 'Start Teaching' | i18n }}</a>
+          <a class="btn" href="https://teach.mozilla.org?ref=webmaker_homepage_promo&utm_campaign=webmaker_homepage_promo&utm_source=webmaker.org&utm_medium=referral">{{ 'Start Teaching' | i18n }}</a>
         </div>
       </div>
     </div>