gistfile1.txt

What I am missing is:
```
$ luarocks install luasql-postgres --local
Installing https://luarocks.org/luasql-postgres-2.3.5-2.rockspec

Error: Could not find header file for PGSQL
  No file libpq-fe.h in /usr/local/include
  No file libpq-fe.h in /usr/include
You may have to install PGSQL in your system and/or pass PGSQL_DIR or PGSQL_INCDIR to the luarocks command.
Example: luarocks install luasql-postgres PGSQL_DIR=/usr/local
```

shell.nix

with import <nixpkgs> {};
with luaPackages;

let
  libs = [lua cjson luasocket luasec];
in
stdenv.mkDerivation {
  name = "streamstore-env";
  buildInputs = [
    nginx
    ffmpeg
    libs
    luarocks
    libpqxx
  ];
  shellHook = ''
    export LUA_CPATH="${lib.concatStringsSep ";" (map getLuaCPath libs)}"
    export LUA_PATH="${lib.concatStringsSep ";" (map getLuaPath libs)}"
    export PGSQL_INCDIR=${postgresql}/include
    export PGSQL_LIBDIR=${postgresql.lib}/lib
    luarocks install penlight --local
  '';
}