Attempting to set *.localhost names in .env causes router to crash

[nballenger]

Hey, @sabman -- I pulled this down and built it, but I'm a bit confused about what are valid params to have in the .env file. I tried using the following:

ENVIRONMENT=development
DOMAINS=sabman.localhost
EMAIL=<MY EMAIL>
PUBLIC_HOST=sabman.localhost
PUBLIC_PROTOCOL=https
PUBLIC_PORT=443
DEFAULT_USER=nick
DEFAULT_PASSWORD=abc123def
POSTGRES_USER=postgres

When I build it with those values and bring the cluster up, the router container dies, with what I'm assuming is a failure message back from letsencrypt:

cartodb-router     | An unexpected error occurred:
cartodb-router     | The request message was malformed :: Error creating new authz :: Name does not end in a public suffix
cartodb-router exited with code 1

Do I need a fully qualified domain name in the .env file for it to work?