Remove the SFTP file storage backend. Downstream users can use either sshfs (which is what Danbooru now uses in production) or rclone instead. The Ruby SFTP gem was much slower than sshfs.
Config
This directory contains configuration files for Danbooru.
To configure your Danbooru instance, copy danbooru_default_config.rb to danbooru_local_config.rb and edit it. See danbooru_default_config.rb for details.
The only file here that end users need to be concerned about is danbooru_default_config.rb. The rest of the files here are internal Rails-related configuration files that end users shouldn't need to edit.