Update index.jade

Author: mgonto

views/index.jade

@@ -19,11 +19,11 @@ block content
         a(href='http://swag.auth0.com/', target='_blank') Get a T-shirt!
 
       .social
-        a.a0(href='https://auth0.com/', target='_blank')
+        a.a0(href='https://auth0.com/%3Cspan%20class="x x-first x-last">?utm_source=jwtio&utm_campaign=craftedby', target='_blank')
           span.by-text Crafted by
           img(src='/img/pic_logo_ft.svg', alt='Token Based Authentication')
 
-      a.supported(href='https://auth0.com/', target="_blank")
+      a.supported(href='https://auth0.com/%3Cspan%20class="x x-first x-last">?utm_source=jwtio&utm_campaign=craftedby', target="_blank")
           | Supported by
           img(src='/img/ico_logo.svg', alt='Token Based Authentication')