添加七牛cdn上传功能

views/admin/backLayout.html

@@ -8,7 +8,6 @@
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <title>{{.Title}}</title>
     <meta name="robots" content="noindex, nofollow">
-    <link rel="stylesheet" href="/static/admin/background.css">
     <link rel="stylesheet" href="/static/admin/style.css">
     <!--[if lt IE 9]>
         <script src="//cdn.bootcss.com/html5shiv/3.7.2/html5shiv.min.js"></script>