Upgrade bootsnap to 1.9.3 too because Ruby 3.0.3 has a bug that causes Rails to fail to boot when bootsnap is enabled. Bootsnap 1.9.3 works around this bug. Also add libgmp to build with bignum support.
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.