fix migration script
deployment: allow to choose not the latest version, but the previous version, to be able to re-publish a version
Merge pull request #19 from passerellesnumeriques/Branch_0.0.79

fix migration script
Merge branch 'master' of https://github.com/passerellesnumeriques/Students-Database into dev

Conflicts:
	deploy/version_and_path_form.php
SQLQuery for production: avoid WHERE IN () or insert nothing. Keep it for development, to force developers to avoid unuseful database requests, but avoid problems in production if ever some checks are missing.