Revert "remove postgres and liquibase from travis.yml"
Revert "remove postgres and liquibase from travis.yml"

This reverts commit a9e0489d6165cff765c7201d26c36ee44db567f9.

samsalisbury/sous,opentable/sous,samsalisbury/sous,opentable/sous,samsalisbury/sous,samsalisbury/sous,samsalisbury/sous,opentable/sous,opentable/sous,opentable/sous