Minor updates to postgresql_service.rst

I've added the steps that were missing/wrong for me when I went through this just now.
tell the new developer how they can replace the real docker binary with the one they've been hacking on (#2142)
Merge pull request #2142 from SvenDowideit/patch-1

tell the new developer how they can replace the real docker binary with ...
Merge pull request #2160 from iffy/patch-1

Minor updates to postgresql_service.rst
Prevent docker-ci to test closing PRs
Merge pull request #2211 from mzdaniel/2190-docker-ci

Prevent docker-ci to test closing PRs
Provide a synced folder for the virtualbox provisioner

By default, spinning up a VM using the VirtualBox provisioner doesn't
set a synced folder which means local development (beyond toying with
docker commands) can't really happen.

This fixes that and means local development can occur.
Add 'Kushal Pisavadia' to AUTHORS file