nix: add channel configuration and rework update process

nix/home-manager/configuration/root.nix

@@ -0,0 +1,35 @@
+{ pkgs
+, config, 
+... }:
+
+let
+  # gitpkgs = import /home/steveej/src/github/NixOS/nixpkgs {};
+  # unstablepkgs = import <nixos-unstable> {};
+
+in {
+  imports = [
+    ../profiles/common.nix
+    ../profiles/nix-channels.nix
+    ../programs/neovim.nix
+    ../programs/zsh.nix
+  ];
+
+  nixpkgs.config = {
+    packageOverrides = pkgs: with pkgs; {
+    };
+  };
+
+  home.sessionVariables = {
+  };
+
+  home.packages = []
+    ++ (with pkgs; [
+      # Authentication
+      mkpasswd
+
+      # Version Control Systems
+      git-crypt
+      gitFull
+      mr
+  ]); 
+}