Add a model for storing image and video metadata for uploaded files. Metadata is extracted using ExifTool. You will need to install ExifTool after this commit. ExifTool 12.22 is the minimum required version because we use the `--binary` option, which was added in this release. The MediaMetadata model is separate from the MediaAsset model because some files contain tons of metadata, and most of it is non-essential. The MediaAsset model represents an uploaded file and contains essential metadata, like the file's size and type, while the MediaMetadata model represents all the other non-essential metadata associated with a file. Metadata is stored as a JSON column in the database. ExifTool returns all the file's metadata, not just the EXIF metadata. EXIF is one of several types of image metadata, hence why we call it MediaMetadata instead of EXIFMetadata.
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.