Remove `merge_trains_enabled` column from `project_ci_cd_settings` table
Problem
Since "Allow Merge Train" option is enabled by default from GitLab 12.1 (See https://gitlab.com/gitlab-org/gitlab-ee/issues/11222), we should drop the merge_trains_enabled
column from project_ci_cd_settings
table.
Update
Following reviewer advice !19695 (comment 242909595), this issue will be split into 3 MRs.
- mark the column - 12.5 - !19695 (merged)
- drop the column - 12.7 - !19701 (merged)
- remove the mark - 12.8 - #36461 (comment 269438683)
See also !19701 (comment 269417352)
Edited by Sean Carroll