upgrade postgres version in container

[tyranja]

• add maker file to be able to use a dump
• fixing bundler version

for fixing the bundle version error:

in our Dockerfile we write

RUN gem update --system

and that:

updates RubyGems itself to the latest version.
In recent RubyGems releases (4.x), Bundler 4 is now installed by default as part of the update.

Siehe:https://github.com/rubymonsters/speakerinnen_liste/actions/runs/20348671815/job/58726229190#step:4:221

[zaziemo]

Hmm, irgendwie kommt bei mir immer noch die Fehlermeldung:

psql: error: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: No such file or directory
	Is the server running locally and accepting connections on that socket?
make: *** [restore-db] Error 2