diff --git a/lock.json b/lock.json
index 046a779..30a8aa3 100644
--- a/lock.json
+++ b/lock.json
@@ -1 +1,16 @@
-{"depends":[{"method":"fetchzip","packages":["npeg"],"path":"/nix/store/ffkxmjmigfs7zhhiiqm0iw2c34smyciy-source","ref":"1.2.1","rev":"26d62fdc40feb84c6533956dc11d5ee9ea9b6c09","sha256":"0xpzifjkfp49w76qmaylan8q181bs45anmp46l4bwr3lkrr7bpwh","srcDir":"src","url":"https://github.com/zevv/npeg/archive/26d62fdc40feb84c6533956dc11d5ee9ea9b6c09.tar.gz"}]}
+{
+  "depends": [
+    {
+      "method": "fetchzip",
+      "packages": [
+        "npeg"
+      ],
+      "path": "/nix/store/ffkxmjmigfs7zhhiiqm0iw2c34smyciy-source",
+      "ref": "1.2.1",
+      "rev": "26d62fdc40feb84c6533956dc11d5ee9ea9b6c09",
+      "sha256": "0xpzifjkfp49w76qmaylan8q181bs45anmp46l4bwr3lkrr7bpwh",
+      "srcDir": "src",
+      "url": "https://github.com/zevv/npeg/archive/26d62fdc40feb84c6533956dc11d5ee9ea9b6c09.tar.gz"
+    }
+  ]
+}
diff --git a/shell.nix b/shell.nix
index 24f8937..3a6cdd4 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,2 +1,5 @@
 { pkgs ? import <nixpkgs> { } }:
-pkgs.nim2Packages.buildNimPackage { name = "dummy"; }
+pkgs.buildNimPackage {
+  name = "dummy";
+  lockFile = ./lock.json;
+}