Added serversession-backend-acid-state.

[alaendle]

Hi @meteficha, could/should we add this package? I mean more for consistency reasons - the other backends are also present. However, the tests are currently failing. Just want to collect your feedback - and as a handle to discuss this I created this PR. No pressure.

Checklist:

• Meaningful commit message, eg add my-cool-package (please don't mention build-constraints.yml)
• At least 30 minutes have passed since uploading to Hackage
• If applicable, required system libraries are added to 02-apt-get-install.sh or 03-custom-install.sh
• (recommended) Package have been verified to work with the latest nightly snapshot, e.g by running the verify-package script
• (optional) Package is compatible with the latest version of all dependencies (Run cabal update && cabal outdated)

The script runs virtually the following commands in a clean directory:

  stack unpack $package-$version # `-$version` is optional
  cd $package-$version
  rm -f stack.yaml && stack init --resolver nightly --ignore-subdirs
  stack build --resolver nightly --haddock --test --bench --no-run-benchmarks

[meteficha]

Hi! I haven’t used these packages in many years. I think @ncaq is probably a better person to answer this question.

[ncaq]

@meteficha
I certainly haven't updated it much, but that's because I don't really need much more functionality.
And serversession doesn't really need to keep up with other libraries.
Once a web service is launched, it is often left to just keep running, and serversession itself is not dead.
In fact, I use serversession to run my services.
I would be happy if the related packages were included in the LTS, as I would like to update it to address vulnerabilities.