Add index on ci_commits(gl_project_id)

CREATE INDEX CONCURRENTLY index_ci_commits_on_gl_project_id ON ci_commits (gl_project_id);

This stopped gitlab.com from burning down just now.

cc @yorickpeterse @ayufan

Milestone changed to 8.1

Reassigned to @yorickpeterse

We should add normal ActiveRecord index.

mentioned in commit c6be5006

Since we manually created this index on gitlab.com we'll also need to manually insert the version into the schema_migrations table using (version as per !1616 (merged)):

insert into schema_migrations values ('20151016131433');

Other users won't have to do this, they can just run the database migrations as they usually would.

Just added this entry to schema_migrations.

mentioned in issue #3078 (closed)

Status changed to closed by commit c6be5006