If you are a DIRAC developer and want to appear on this map, then find yourself on Google Maps, right-click, then on "What's here?", then you see the coordinates. Send these to Radovan Bast (lastname at kth dot se).
Alternatively you can also add yourself directly via fork/pull-request. For this please note that Google Maps gives the coordinates in reverse order with respect to GeoJSON. So swap them around before pasting them to developers.geojson.