Extend site model with storage for a defaultRoomID.
Extend site model with storage for a defaultRoomID.

This is used in conjunction with autopromote to allow homecloud
to auto-promote all newly created devices.

Signed-off-by: Jon Seymour <44f878afe53efc66b76772bd845eb65944ed8232@ninjablocks.com>

ninjasphere/go-ninja,ninjasphere/go-ninja