Custom docker image via nix for gitlab CI

1 job for master in 21 seconds (queued for 2 seconds)
Status Name Job ID Coverage
failed build #1084


Name Stage Failure
build Test There is an unknown failure, please try again
Skipping Git submodules setup
$ cabal test
Config file path source is default config file.
Config file //.cabal/config not found.
Writing default configuration to //.cabal/config
No cabal.project file or cabal file matching the default glob './*.cabal' was found.
Please create a package description file <pkgname>.cabal or a cabal.project file referencing the packages you want to build.

ERROR: Job failed: exit code 1