chore: add flake.nix

.gitignore

@@ -42,3 +42,5 @@ generated.gql
 junit.xml
 
 .next
+
+.direnv

flake.nix

@@ -0,0 +1,45 @@
+{
+  description = "Galoy dev environment";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    flake-utils,
+  }:
+    flake-utils.lib.eachDefaultSystem (system: let
+      overlays = [
+        (self: super: {
+          nodejs = super.nodejs_20;
+          yarn = super.yarn.override {
+            nodejs = super.nodejs_20;
+          };
+        })
+      ];
+      pkgs = import nixpkgs {inherit overlays system;};
+      nativeBuildInputs = with pkgs; [
+        nodejs
+        tilt
+        yarn
+        alejandra
+        gnumake
+        docker-compose
+        shellcheck
+        shfmt
+        vendir
+        jq
+        ytt
+      ];
+    in
+      with pkgs; {
+        devShells.default = mkShell {
+          inherit nativeBuildInputs;
+        };
+
+        formatter = alejandra;
+      });
+}