a year went byHEADmain

This does many meta-things, but changes no functionality:
 - get rid of stack, and use just cabal with a stackage snapshot instead
   (why did I ever think stack was a good idea?)
 - update the stackage snapshot to something halfway recent
 - thus making builds work on nixpkgs-23.05 (current stable)
 - separating out packages into their own cabal files
 - use the GHC2021 set of extensions as default
 - very slight code changes to make things build again
 - update readme accordingly
 - stylish-haskell run

1 files changed, 12 insertions, 37 deletions

diff --git a/Readme.md b/Readme.md
index 1960b51..0f66439 100644
--- a/Readme.md
+++ b/Readme.md
@@ -20,48 +20,23 @@ repositories in `config.toml`, then visit `localhost:8080/admin/overview`.
 
 ## Installing
 
-### From the CI pipeline
-
-Gitlab [automatically builds a version](https://git.cccv.de/hub/walint/-/jobs)
-of `walint` each time something is pushed to the version of this repository
-kept at the CCCV infra. The resulting binary should work fine on most linux 
-systems, especially if they're vaguely debian-like.
-
-In case you get an incomprehensible or confusing error when executing it, try 
-running `ldd walint` and see if anything is marked as not found, then install 
-it.
-
-### Build using stack
-
-This uses a lockfile to pin versions of dependencies (as well as `ghc`, the 
-haskell compiler). You will need 
-[the haskell stack](https://docs.haskellstack.org/en/stable/README/).
-
-Run
-
-```
-stack build
-```
-
-If you lack `ghc` and don't know how to install it, you can add  `--install-ghc`,
-and `stack` will take care of that for you (note that on NixOS, `stack` may
-use a fitting `ghc` derivation if it finds one, even without `--install-ghc`).
-
-To install into your `$PATH`, use
+### Build using cabal
 
-```
-stack install
-```
+Build using
 
-Alternatively, run `walint` via stack:
+~~~sh
+cabal build [all|walint|server]
+~~~
 
-```
-stack run -- walint [options as normal]
-```
+There are no version bounds in the cabal files, but the `cabal.project` file
+tells cabal to follow a stackage snapshot.
 
-### Build using cabal
+### Build using Nix
 
-You can, but probably should not. Beware of older Aeson versions!
+Since nixpkgs also follows stackage snapshots, building the packages with Nix
+should work without difficulty; just pass a nixpkgs to `default.nix` which does
+not diverge too much from the currently-used stackage snapshot (aim is that
+stable nixpkgs should work).
 
 ## Usage
 ``` sh