Set travis postgres version to 9.6
Set travis postgres version to 9.6

It defaults to 9.1, and we need 9.6 for our application.

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