chore: adds nix and nixflakes environment

Author: cristianoliveira

.gitignore

@@ -43,3 +43,5 @@ Thumbs.db
 
 .opencode/
 
+# Nix specific files when running 'nix build'
+result

default.nix

@@ -0,0 +1,38 @@
+{ pkgs ? import <nixpkgs> {} }:
+  let
+    lib = pkgs.lib;
+  in
+    pkgs.buildGoModule rec {
+      name = "opencode";
+      version = "0.0.34";
+
+      src = pkgs.fetchFromGitHub {
+        owner = "opencode-ai";
+        repo = "opencode";
+        tag = "v${version}";
+        hash = "sha256-EaspkL0TEBJEUU3f75EhZ4BOIvbneUKnTNeNGhJdjYE=";
+      };  
+
+      vendorHash = "sha256-cFzkMunPkGQDFhQ4NQZixc5z7JCGNI7eXBn826rWEvk=";
+
+      checkFlags =
+      let
+        skippedTests = [
+          # permission denied
+          "TestBashTool_Run"
+          "TestSourcegraphTool_Run"
+          "TestLsTool_Run"
+        ];
+      in
+      [ "-skip=^${lib.concatStringsSep "$|^" skippedTests}$" ];
+
+      meta = with lib; {
+        description = "A powerful terminal-based AI assistant for developers, providing intelligent coding assistance directly in your terminal.";
+        homepage = "https://github.com/opencode-ai/opencode";
+        mainProgram = "opencode";
+        license = licenses.mit;
+        maintainers = with maintainers; [
+          zestsystem
+        ];
+      };
+    }

flake.lock

@@ -0,0 +1,31 @@
+{
+  description = "Opencode's nix flake";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs";
+    utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { nixpkgs, utils, ... }: 
+    utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+        defaultPkg = pkgs.callPackage ./default.nix {
+          inherit pkgs;
+        };
+      in {
+        devShells.default = pkgs.mkShell {
+          packages = with pkgs; [
+            # Development tools
+            go
+            
+            # Aux tools
+            goreleaser
+          ];
+        };
+
+        packages = {
+          default = defaultPkg;
+        };
+    });
+}