add build for documentation pdf

.gitignore

@@ -1,2 +1,3 @@
 /*.pdf
 /pack
+/result

README.md

@@ -88,6 +88,12 @@ You can build (and view) it by running:
 make
 ```
 
+Or when using Nix:
+
+```sh
+nix build
+```
+
 This will compile it once and open it using `xdg-open`.
 
 ### Building thesis examples

flake.nix

@@ -8,10 +8,27 @@
     utils.lib.eachDefaultSystem (system:
       let
         pkgs = import nixpkgs { inherit system; };
+        dependencies = with pkgs; [ typst gnumake jq xdg-utils zip ];
       in
       {
+        packages.documentation = pkgs.stdenv.mkDerivation {
+          pname = "documentation";
+          version = "1.2";
+          src = ./.;
+          buildInputs = dependencies;
+          buildPhase = ''
+            make documentation.pdf
+          '';
+          installPhase = ''
+            mkdir -p $out
+            cp -r documentation.pdf $out/ || true
+          '';
+        };
+
+        packages.default = self.packages.${system}.documentation;
+
         devShell = with pkgs; mkShell {
-          buildInputs = [ typst gnumake jq xdg-utils zip ];
+          buildInputs = dependencies;
         };
       }
     );