Migrate from SQLite to MySQL

GitLab ceases to support SQLite from v4.0 onwards. If you are still using SQLite follow these steps in order to migrate your data from SQLite to MySQL.

1. Update to the latest GitLab
2. Run bundle exec rake db:data:dump RAILS_ENV=production to extract the data currently stored in SQLite.
3. Follow the database setup guide to install MySQL and update your database.yml
4. Run bundle exec rake db:setup RAILS_ENV=production to setup your database tables in MySQL.
5. Run bundle exec rake db:data:load RAILS_ENV=production to load the data saved in step 2 into MySQL.
6. Rename your db/production.sqlite file (don't delete it yet).
7. Restart GitLab and test if all the data has been transfered correctly.
8. Delete your db/*.sqlite files, if you are sure everything worked.