- Don't use `TableReferences` - using `.arel_table` is shorter!
- Move some database-related code to `Gitlab::Database`
- Remove the `MergeRequest#issues_closed` and
`Issue#closed_by_merge_requests` associations. They were either
shadowing or were too similar to existing methods. They are not being
used anywhere, so it's better to remove them to reduce confusion.
- Use Rails 3-style validations
- Index for `MergeRequest::Metrics#first_deployed_to_production_at`
- Only include `CycleAnalyticsHelpers::TestGeneration` for specs that
need it.
- Other minor refactorings.
1. Change multiple updates to a single `update_all`
2. Use cascading deletes
3. Extract an average function for the database median.
4. Move database median to `lib/gitlab/database`
5. Use `delete_all` instead of `destroy_all`
6. Minor refactoring
- These are not being used anymore.
- Consolidate all issue metrics into a single migration.
- Consolidate all merge request metrics into a single migration.
1. Record the `wip_flag_first_removed_at` and
`first_assigned_to_user_other_than_author` metrics for a merge
request. Use a `merge_request_metrics` table, similar to the one for
`issues`. Metrics are recorded `after_save`.
2. Move larger queries to a `CycleAnalytics::Queries` module.
