flake: add shell

flake.nix

@@ -1,15 +1,29 @@
 {
   description = "zremap nix flake";
 
-  outputs = { self, nixpkgs }: {
-
-    defaultPackage.x86_64-linux =
-      with import nixpkgs { system = "x86_64-linux"; };
+  outputs = {
+    self,
+    nixpkgs,
+  }: {
+    defaultPackage.x86_64-linux = with import nixpkgs {system = "x86_64-linux";};
       stdenv.mkDerivation {
         pname = "zremap";
         version = "0.1";
         src = self;
-        nativeBuildInputs = [ zig.hook ];
+        nativeBuildInputs = [zig.hook];
+        buildInputs = [libevdev];
+      };
+
+    devShells.x86_64-linux.default = with import nixpkgs {system = "x86_64-linux";};
+      mkShell {
+        buildInputs = [
+          libevdev
+          zig
+        ];
+
+        shellHook = ''
+          echo "happy hacking!"
+        '';
       };
   };
 }