[PATCH v2 4/4] Test postgresql support in Travis CI

[Stephen Finucane]

On Fri, 2017-10-20 at 16:36 +1100, Daniel Axtens wrote:
> Use the most recent version of postgres (9.6) because we need a
> more recent version than the default to show up the broken
> bundle behaviour.
> 
> This should prevent us from causing any further regressions.
> 
> Signed-off-by: Daniel Axtens <dja at axtens.net>

All my questions from v1 are addressed.

Reviewed-by: Stephen Finucane <stephen at that.guru>