Linux: How to install DBD::Pg module?
Just ran into this issue, and on Ubuntu 16.04 Xenial the package you're looking for is:
apt-get install libdbd-pg-perl
You have to install libpq-dev, e.g. on Ubuntu:
sudo apt-get install libpq-dev
On CentOS/RH you can fix it by installing perl-DBD-Pg package with yum
sudo yum install perl-DBD-Pg