Move to travis trusty beta for postgres 9.6 support
Move to travis trusty beta for postgres 9.6 support

See https://docs.travis-ci.com/user/database-setup/#Using-a-different-PostgreSQL-Version

OpenEnergyDashboard/OED,beloitcollegecomputerscience/OED,OpenEnergyDashboard/OED,beloitcollegecomputerscience/OED,OpenEnergyDashboard/OED,beloitcollegecomputerscience/OED,beloitcollegecomputerscience/OED,OpenEnergyDashboard/OED