Github Ribbon z-index fix.

Author: loicfrering

_layouts/default.html

@@ -26,8 +26,8 @@
 
   <div id="container">
     <header>
-      <a href="http://github.com/pullrequest"><img style="position: absolute; top: 0; right: 0; border: 0;" src="https://a248.e.akamai.net/assets.github.com/img/abad93f42020b733148435e2cd92ce15c542d320/687474703a2f2f73332e616d617a6f6e6177732e636f6d2f6769746875622f726962626f6e732f666f726b6d655f72696768745f677265656e5f3030373230302e706e67" alt="Fork me on GitHub"></a>
       <h1><a href="/" title="Page d'accueil"><img src="/public/img/pullrequest-logo.png" alt="PullRequest"/></a></h1>
+      <a href="http://github.com/pullrequest"><img style="position: absolute; top: 0; right: 0; border: 0; z-index: 1;" src="https://a248.e.akamai.net/assets.github.com/img/abad93f42020b733148435e2cd92ce15c542d320/687474703a2f2f73332e616d617a6f6e6177732e636f6d2f6769746875622f726962626f6e732f666f726b6d655f72696768745f677265656e5f3030373230302e706e67" alt="Fork me on GitHub"></a>
     </header>
 
     <div id="main" role="main">