build(nix): nix environment

.gitignore

@@ -10,3 +10,6 @@ erl_crash.dump
 # SQLite
 *.sqlite3
 *.db
+
+# Nix
+result

flake.nix

@@ -0,0 +1,35 @@
+{
+  description = "Moe-Counter Compatible Website Hit Counter";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    nix-gleam.url = "github:arnarg/nix-gleam";
+    gitignore = {
+      url = "github:hercules-ci/gitignore.nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+  outputs = { self, nixpkgs, flake-utils, nix-gleam, gitignore, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [
+            nix-gleam.overlays.default
+          ];
+        };
+        inherit (gitignore.lib) gitignoreSource;
+      in
+      {
+        packages.default = pkgs.buildGleamApplication {
+          src = gitignoreSource ./.;
+          rebar3Package = pkgs.rebar3WithPlugins {
+            plugins = with pkgs.beamPackages; [ pc ];
+          };
+        };
+        devShell = pkgs.mkShell {
+          buildInputs = [ pkgs.gleam pkgs.rebar3 ];
+        };
+      }
+    );
+}