* add Nix support
* fix formatter output
* mention Nix in README
* fix common import
* fix frontend old version import
* clarified flake pkgs order
* rm old dataDir option
* comment typo
* fix password assertion
* rm old User/Group logic
* rewrite assertion boolean expr
* General flake touchup
- Rewrite `callPackage` exprs to be more readable
- Add pre-commit support for devShell
- Add direnv support
* add simple test
* use correct test func
