flake: migrate to flake with numtide/blueprint

Author: aster-void

.envrc

@@ -1 +1 @@
-use nix
+use flake

flake.lock

@@ -0,0 +1,22 @@
+{
+  description = "Simple flake with a devshell";
+
+  # Add all your dependencies here
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs?ref=nixos-unstable";
+    blueprint.url = "github:numtide/blueprint";
+    blueprint.inputs.nixpkgs.follows = "nixpkgs";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  # Load the blueprint
+  outputs = inputs:
+    inputs.blueprint {
+      inherit inputs;
+      prefix = "nix/";
+      nixpkgs.overlays = [
+        inputs.rust-overlay.overlays.default
+      ];
+    };
+}

flake.nix

@@ -1,12 +1,4 @@
-{
-  pkgs ?
-    import <nixpkgs> {
-      overlays = [
-        rust-overlay.overlays.default
-      ];
-    },
-  rust-overlay ? builtins.getFlake "github:oxalica/rust-overlay",
-}: let
+{pkgs}: let
   rustToolchain = pkgs.rust-bin.stable.latest.default.override {
     extensions = ["rust-src"];
   };