[20181010180900] Convox Test, Postgres 10, Linux Local Rack

[ddollar]

This release adds a new test: attribute to services in convox.yml and a convox test command for building the app and executing its tests on the resulting release.

# build a new release and run tests for all services that define them
$ convox test

# run tests against an existing release
$ convox test --release R123456789

• #2974 escape command args in systemd [@ddollar]
• #2976 add convox test for testing apps on a rack [@ddollar]
• #2977 use correct postgres 10 parameter group format [@ddollar]