readme update; nix flake; hints on how to run.

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -1,3 +1,7 @@
 .spago/
 output/
 node_modules/
+.psci_modules
+
+# Nix
+.direnv/

README.md

@@ -43,7 +43,7 @@ instance graphqlReactFinlandConference ::
         }
     )
 
-client :: GraphQLClient
+client :: GraphQLClientAff
 client = graphQL "https://api.react-finland.fi/graphql" [] driver
 
 main ∷ Effect Unit
@@ -57,3 +57,40 @@ main =
 ```
 
 You can check out the [test](./test/Main.purs) for a full example.
+
+## Development
+
+You can either use the nix shell, or the npm package.
+
+### Nix shell
+
+Having set up [flakes](https://nixos.wiki/wiki/Flakes), either using [direnv](https://direnv.net/) (`direnv allow`) or `nix develop`
+
+Buliding:
+
+```
+spago build
+```
+
+Testing:
+
+```
+spago -x test.dhall test
+```
+
+
+### Npm
+
+Just run `npm i` and then:
+
+Building:
+
+```
+spago build
+```
+
+Testing:
+
+```
+npm run test
+```

flake.nix

@@ -0,0 +1,51 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.05";
+    easy-purescript-nix = {
+      url = "github:justinwoo/easy-purescript-nix";
+      flake = false;
+    };
+    flake-compat = {
+      url = "github:edolstra/flake-compat";
+      flake = false;
+    };
+  };
+
+  outputs = { self, nixpkgs, easy-purescript-nix, ... }@inputs:
+    let
+      name = "purescript-graphql-fundeps";
+
+      supportedSystems = [
+        "aarch64-darwin"
+        "x86_64-darwin"
+        "x86_64-linux"
+      ];
+
+      forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: f system);
+    in
+    {
+      devShell = forAllSystems (system:
+        let
+          pkgs = import nixpkgs { inherit system; };
+
+          easy-ps = import easy-purescript-nix { inherit pkgs; };
+        in
+        pkgs.mkShell {
+          inherit name;
+          buildInputs = (with pkgs; [
+            nodejs_20
+            nixpkgs-fmt
+          ]) ++ (with easy-ps; [
+            purs
+            purs-tidy
+            psa
+            spago
+            purescript-language-server
+          ]) ++ (pkgs.lib.optionals (system == "aarch64-darwin")
+            (with pkgs.darwin.apple_sdk.frameworks; [
+              Cocoa
+              CoreServices
+            ]));
+        });
+    };
+}