auth_user directive (per database entry) wrongly translated to user

[ardumont]

Hello,

I'd like to use the auth_user directive on a per database basis. So far i
cannot (example at [2]), as the auth_user directive is translated as user
directive [1].

Those are not the same though.

From the documentation [2], auth_user allows to avoid specifying the
credentials in the pgbouncer configuration (and queries that information
instead to retrieve those information).

auth_user directive (global):

If auth_user is set, any user not specified in auth_file will be queried through
the auth_query query from pg_shadow in the database using auth_user. Auth_user’s
password will be taken from auth_file.

user directive (per database entry):

If user= is set, all connections to the destination database will be done with
the specified user, meaning that there will be only one pool for this database.

auth_user directive (per database entry):

Override of the global auth_user setting, if specified.

I shall propose a PR to adapt accordingly.
I have in mind to propose the use of both user and auth_user.
Then that'd be the client of this module to decide to use whatever she needs.

Note:
I tried to use the global directive auth_user (not specifying it on a per database entry) but:

1. It's limited as we could have multiple different auth_user needed anyway
2. It does not work (then again it's a pgbouncer problem, not this module's)

[1] https://github.com/covermymeds/puppet-pgbouncer/blob/master/templates/pgbouncer.ini.databases.part2.erb#L4

[2] https://forge.softwareheritage.org/D1550

[3] https://pgbouncer.github.io/config.html

Cheers,
Antoine R. Dumont