csrf-token will be made each time. 

when generating statics page,

```
$ rake staticman:build
```

each time generated page's csrf-token has changed.

```
-<meta content="9y9zlzk6oD6a7ITBoovBJMwYzGJ1ZELah5QGV3dwK0s=" name="csrf-token" />
+<meta content="WBbubz6haUfBKVDg2VgYQTfk4yn3Vmk/soVpWuNUvuk=" name="csrf-token" />
```

I do not want to add change to csrf-token, aren't there any good methods? 
