Tools for the doctrine migration bundle
composer require a5sys/doctrine-migration-tools-bundle
The diff command of doctrine generate the version file from the diff between your database and the current schema.
This command generate the version from the diff between the schema stored in a file and your current schema.
So you only have to run the command before doing a new version of your app.
php bin/console doctrine:migrations:diff-file
A version file will be generated (if required) and your current schema will be dumped in a file. (in /app/DoctrineMigrations/SchemaVersion)