Breaking change to Pupperware compose file

[Nate Wolfe]

Hello,

We made a breaking change to the pupperware docker-compose.yml file here: https://github.com/puppetlabs/pupperware/pull/17

We introduced a root-level "volumes/" directory, so to upgrade you'll need to:

1. docker-compose down

2. mkdir volumes

3. mv code puppet serverdata puppetdb puppetdb-postgres volumes/

4. docker-compose up