Install fails on fresh LXC container because ca-certificates is not installed

[clonedagain]

I've had a problem using the role on a fresh container installed with Ubuntu 14.04.2 as host and guest, simply because the minimal installation in the LXC guest does not contain CA certificates to validate www.postgresql.org: msg: Failed to validate the SSL certificate for www.postgresql.org:443. Use validate_certs=no or make sure your managed systems have a valid CA certificate installed. Paths checked for this platform: /etc/ssl/certs, /etc/pki/ca-trust/extracted/pem, /etc/pki/tls/certs, /usr/share/ca-certificates/cacert.org, /etc/ansible.

It can be worked around by installing the package ca-certificates manually.
I suppose installing it from the role would be an acceptable fix too.