The *dch-webhooks* user is used by *dch-webhooks* in order to publish
host information when a new machine triggers its _POST /host/online_
webhook. It therefore needs to be able to write to the
_host-provisioner_ queue (via the default exchange).
The *host-provisioner* user is used by the corresponding consumer to
receive the host information and initiate the provisioning process.
Dustin
3255edc7b6