Merge pull request #93 from coderdojo-japan/force-load-css

cssが更新されるように適当なパラメータをcssのパスに追加

Author: kp54

_includes/head.html

@@ -64,5 +64,5 @@
 
   <!-- CSS -------------------------- -->
   <!-- DojoCon CSS -->
-  <link rel="stylesheet" href="/css/main.css" />
+  <link rel="stylesheet" href="/css/main.css?7f8c4bb4" />
 </head>