1. To ensure that all legacy epic records (in our case: `epic_issues` and `related_epic_links`) have a work item equivalent (`work_item_parent_links` and `issue_links`) we want to add foreign keys with a NOT NULL constraint to these tables. 2. In addition to that we want to re-sync the data before we release epic work items. 3. This will also help us in the future to not sync information from the work item to the legacy epic as we can query the data from the work item records. 4. It will also help us with ensuring that data is correctly deleted when deleted on the work item side.