Add flake to build for nix, does not work yet

Error: Some binaries contain forbidden references to /build/ (libpdfrx)

flake.nix

@@ -0,0 +1,31 @@
+{
+  description = "A digital sheet reader app and more.";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/94def634a20494ee057c76998843c015909d6311";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = {
+    nixpkgs,
+    flake-utils,
+    ...
+  }:
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        pkgs = import nixpkgs {inherit system;};
+      in {
+        packages = rec {
+          sheetless = pkgs.flutter.buildFlutterApplication {
+            pname = "sheetless";
+            version = "0.1.2";
+
+            src = ./.;
+            autoPubspecLock = ./pubspec.lock;
+          };
+
+          default = sheetless;
+        };
+      }
+    );
+}