📌 properly pin versions

nix/sources.json

@@ -1,14 +1,26 @@
 {
+    "home-manager": {
+        "branch": "master",
+        "description": "Manage a user environment using Nix  [maintainer=@rycee] ",
+        "homepage": "https://nix-community.github.io/home-manager/",
+        "owner": "nix-community",
+        "repo": "home-manager",
+        "rev": "6d9bff77eda4426b7b9a5e8f0e9b94fe47798582",
+        "sha256": "0zj5syvapbb3smn5zp6dvax4vrw0kzl7wh81hg1kbi7j8qild73v",
+        "type": "tarball",
+        "url": "https://github.com/nix-community/home-manager/archive/6d9bff77eda4426b7b9a5e8f0e9b94fe47798582.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
     "niv": {
         "branch": "master",
         "description": "Easy dependency management for Nix projects",
         "homepage": "https://github.com/nmattia/niv",
         "owner": "nmattia",
         "repo": "niv",
-        "rev": "1819632b5823e0527da28ad82fecd6be5136c1e9",
-        "sha256": "08jz17756qchq0zrqmapcm33nr4ms9f630mycc06i6zkfwl5yh5i",
+        "rev": "e0ca65c81a2d7a4d82a189f1e23a48d59ad42070",
+        "sha256": "1pq9nh1d8nn3xvbdny8fafzw87mj7gsmp6pxkdl65w2g18rmcmzx",
         "type": "tarball",
-        "url": "https://github.com/nmattia/niv/archive/1819632b5823e0527da28ad82fecd6be5136c1e9.tar.gz",
+        "url": "https://github.com/nmattia/niv/archive/e0ca65c81a2d7a4d82a189f1e23a48d59ad42070.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs": {
@@ -17,10 +29,10 @@
         "homepage": "",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "d8eb97e3801bde96491535f40483d550b57605b9",
-        "sha256": "1bdd7jinq5d40qai45jfkbcw1n96c7fdlams5iidwzy2ag8axlqh",
+        "rev": "189a13688782682f2022023c025733bfb269f9d3",
+        "sha256": "09a027w36x05c8m8rwa7lr2g4sc12hx502xbkxhrpa3vmcryrc51",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/d8eb97e3801bde96491535f40483d550b57605b9.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/189a13688782682f2022023c025733bfb269f9d3.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }

shell.nix

@@ -1,6 +1,11 @@
-{ pkgs ? import <nixpkgs> { } }:
-
-pkgs.mkShell {
+let
+  sources = import ./nix/sources.nix;
+  pkgs = import sources.nixpkgs { };
+in pkgs.mkShell {
   name = "athens";
   buildInputs = [ pkgs.morph ];
+
+  shellHook = ''
+    export NIX_PATH="nixpkgs=${sources.nixpkgs}:home-manager=${sources.home-manager}:."
+  '';
 }