text: ALTER TABLE draft_document
  ADD COLUMN created TIMESTAMP NULL;
  
  UPDATE draft_document
  SET created = now();
  
  ALTER TABLE draft_document
  ALTER COLUMN created SET NOT NULL;
  
  
  
  ALTER TABLE draft_document
  ADD COLUMN updated TIMESTAMP NULL;
  
  UPDATE draft_document
  SET updated = now();
  
  ALTER TABLE draft_document
  ALTER COLUMN updated SET NOT NULL;
  