Add note about static file permissions to the readme
Add note about static file permissions to the readme

This provides very little information. But I guess most people using
Jester won’t need much more details.

Some sort of documentation was requested¹ by dom96² in the pull request.

¹ https://github.com/dom96/jester/pull/61#issuecomment-209640091
² https://github.com/dom96

idwaker/jester,dom96/jester