Incorporate NixOS configuration

TL;DR:
- Move /etc/nixos/configuration.nix -> //nixos/configuration.nix
- Move /etc/nixos/hardware-configuration.nix -> //nixos/harware.nix
- Document installer.nix
- Create rebuild.nix wrapper around `sudo nixos-rebuild switch`

Previously I sketched ideas for the configuration.nix for socrates -- also known
as flattop -- the inexpensive Acer laptop residing in my flat and stored that
configuration.nix file in briefcase. Now, however, I have successfully installed
NixOS onto socrates. By default NixOS saves the configuration.nix and
hardware-configuration.nix files to /etc/nixos/. I'm moving both of these files
into briefcase.

Because the command `nixos-rebuild` looks for the NixOS configuration
file in /etc/nixos, I wrote rebuild.nix, which creates a program to
call `nixos-rebuild` with the new location of my configuration.nix.

1 files changed, 9 insertions, 0 deletions

diff --git a/nixos/rebuild.nix b/nixos/rebuild.nix
new file mode 100644
index 000000000000..84a8bb05d6bf
--- /dev/null
+++ b/nixos/rebuild.nix
@@ -0,0 +1,9 @@
+{ pkgs ? import <nixpkgs> {}, ... }:
+
+pkgs.writeShellScriptBin "rebuild" ''
+  set -ue
+  sudo nixos-rebuild \
+    -I nixos-config=/home/wpcarro/briefcase/nixos/configuration.nix \
+    -I nixpkgs=/home/wpcarro/nixpkgs \
+    switch
+''