Remove orphaned merge request approvers from the database
My first crack at a migration to remove bad data and finally close https://gitlab.com/gitlab-org/gitlab-ee/issues/1
@ayufan noted that this query may lock the approvers table for too long. He suggests we loop through and do sets of 100 until it's all done. However, I can't make this work in a sane way - mostly due to my own lack of experience here. Rails migration gurus, please help me out and suggest how we can do this.