docs(*): add description

docs/themes/angular-google-maps/layouts/index.html

@@ -92,7 +92,9 @@ <h4 class="mdl-card__title-text">Festa Lá</h4>
                  <h4 class="mdl-card__title-text"><a href="https://city-sightseeing.com" target="_blank" style="color: inherit;text-decoration: none;font-weight: inherit;">City Sightseeing Worldwide</a></h4>
               </div>
               <div class="mdl-card__supporting-text">
-                <span class="mdl-typography--font-light mdl-typography--subhead"></span>
+                <span class="mdl-typography--font-light mdl-typography--subhead">
+                  City Sightseeing is the world's number 1 hop-on hop-off bus tour provider; operating in more than 110 cities. Hop on and hop off as many times as you like at any of the bus stops on the route and see all the best sights and attractions that the town or city has to offer.
+                </span>
               </div>
             </div>