Added CODEOWNERS file to protect DB migrations
Added CODEOWNERS file to protect DB migrations

- DB migrations are risky changes
- require review from devops before merging these

janvt/Ghost,e10/Ghost,janvt/Ghost,kevinansfield/Ghost,JohnONolan/Ghost,JohnONolan/Ghost,ErisDS/Ghost,bitjson/Ghost,bitjson/Ghost,e10/Ghost,TryGhost/Ghost,JohnONolan/Ghost,kevinansfield/Ghost,ErisDS/Ghost,TryGhost/Ghost,TryGhost/Ghost,ErisDS/Ghost,kevinansfield/Ghost