Add tagged link

Author: vctrfrnndz

views/introduction.jade

@@ -45,7 +45,7 @@ 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.twitter(href='https://twitter.com/auth0', target="_blank")