working nix setup and a working database setup

flake.nix

@@ -0,0 +1,41 @@
+{
+  description = "A very basic flake";
+  inputs.haskellNix.url = "github:input-output-hk/haskell.nix";
+  inputs.nixpkgs.follows = "haskellNix/nixpkgs-unstable";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+  outputs = { self, nixpkgs, flake-utils, haskellNix }:
+    flake-utils.lib.eachSystem [ "x86_64-linux" "x86_64-darwin" ] (system:
+    let
+      overlays = [ haskellNix.overlay
+        (final: prev: {
+          # This overlay adds our project to pkgs
+          helloProject =
+            final.haskell-nix.project' {
+              src = ./.;
+              compiler-nix-name = "ghc8107";
+              # This is used by `nix develop .` to open a shell for use with
+              # `cabal`, `hlint` and `haskell-language-server`
+              shell.tools = {
+                cabal = {};
+                hlint = {};
+                haskell-language-server = {};
+              };
+              # Non-Haskell shell tools go here
+              shell.buildInputs = with pkgs; [
+                nixpkgs-fmt
+              ];
+              # This adds `js-unknown-ghcjs-cabal` to the shell.
+              shell.crossPlatform = p: [p.ghcjs];
+            };
+        })
+      ];
+      pkgs = (import nixpkgs { inherit system overlays; inherit (haskellNix) config; }).pkgsCross.ghcjs;
+      flake = pkgs.helloProject.flake {
+        # This adds support for `nix build .#js-unknown-ghcjs-cabal:hello:exe:hello`
+        crossPlatforms = p: [p.ghcjs];
+      };
+    in flake // {
+      # Built by `nix build .`
+      defaultPackage = flake.packages."rcv-site:exe:client";
+    });
+}