DB schema generated by a migration may look different in rails 4 and 5 (because rails 5 may use different default values). For this reason it's important to explicitly set for which rails version a migration was written for. See https://stackoverflow.com/questions/35929869/activerecordmigration-deprecation-warning-asks-for-rails-version-but-im-no/35930912#35930912
[10.3] Migrate `can_push` column from `keys` to `deploy_keys_project` See merge request gitlab/gitlabhq!2276 (cherry picked from commit f6ca52d31bac350a23938e0aebf717c767b4710c) 1f2bd3c0 Backport to 10.3