Add devenv.nix

Must have only Nix and devenv installed

```
devenv shell
cargo build
sudo ./target/debug/framework_tool
```

Signed-off-by: Daniel Schaefer <dhs@frame.work>

Author: JohnAZoidberg

.envrc

@@ -0,0 +1,5 @@
+export DIRENV_WARN_TIMEOUT=20s
+
+eval "$(devenv direnvrc)"
+
+use devenv

.gitignore

@@ -4,3 +4,15 @@ build/
 *.efi
 *.exe
 *.pdb
+
+# Devenv
+.devenv*
+devenv.local.nix
+# Nix
+result*
+
+# direnv
+.direnv
+
+# pre-commit
+.pre-commit-config.yaml

devenv.nix

@@ -0,0 +1,11 @@
+{ pkgs, lib, config, inputs, ... }:
+
+{
+  packages = with pkgs; [
+    systemd # libudev
+  ];
+
+  languages.rust.enable = true;
+  # https://devenv.sh/reference/options/#languagesrustchannel
+  languages.rust.channel = "stable";
+}

devenv.yaml

@@ -0,0 +1,8 @@
+inputs:
+  fenix:
+    url: github:nix-community/fenix
+    inputs:
+      nixpkgs:
+        follows: nixpkgs
+  nixpkgs:
+    url: github:cachix/devenv-nixpkgs/rolling

nix.md

@@ -0,0 +1,12 @@
+# Building with Nix
+
+## Building with devenv
+
+
+Must have Nix and devenv installed
+
+```
+devenv shell
+cargo build
+sudo ./target/debug/framework_tool
+```