In the middle of installing several packages using

    apt-get install postgresql ruby-sass
I get a message.

Setting up postgresql-common (165+deb8u2) ...
supported-versions: WARNING! Unknown distribution: devuan
/usr/share/postgresql-common/supported-versions: 64: /usr/share/postgresql-common/supported-versions: ID_LIKE: parameter not set
/usr/share/postgresql-common/supported-versions: 67: /usr/share/postgresql-common/supported-versions: ID_LIKE: parameter not set
Please submit this as a bug report to your distribution.
Adding user postgres to group ssl-cert

Evidently postgresql doesn't know about devuan.
Could it be because I don't have a /etc/debian_version file, but only
a /etc/devuan_version file? Or does it discover I'm using devuan by
other means?

-- hendrik