hostsname being derived from $HOSTNAME doesn't work well on boot2docker

[danbedard]

Boot2docker containers are available through an internal 192.168 network. But $HOSTNAME resolves to the Mac OSX host's name. Container environment variable $hostsname is set to $HOSTNAME, and the .groovy config file for iDrop-web is populated with this variable as a prefix. Thus, attempts to access iDrop Web fail to find the container.

Either update documentation or update how .groovy file is modified.