add missing @ for twitter username

views/layout.jade

@@ -17,5 +17,5 @@ html
           .navbar-header
             a.navbar-brand(href="/") Crafatar
           .navbar-header
-            a.navbar-brand.twitter(href="https://twitter.com/Crafatar", target="_blank") crafatar
+            a.navbar-brand.twitter(href="https://twitter.com/Crafatar", target="_blank") @crafatar
     block content