Update docs/tutorials/README.md, docs/best-practices/shared-environment.md
update Tutorials readme.md (moved link page from root). Added verbiage about user permissions.
On December 29, GitLab will be migrating to the next generation Container Registry, which implements automatic garbage collection. See KB news article for edge cases in which you could need to rebuild a container after the migration.
update Tutorials readme.md (moved link page from root). Added verbiage about user permissions.