Use nix-env for Discord installation

hosts/home.nix

@@ -60,7 +60,12 @@ in
 
       # GUI applications
       firefox
-      discord
+      #discord
+      # Commented out Discord, it is better to install it with nix-env
+      # using the following command to get past update issues:
+      # nix-env -f https://github.com/NixOS/nixpkgs/archive/master.tar.gz -iA discord
+      # See https://github.com/NixOS/nixpkgs/issues/94806#issuecomment-670213407
+      # This has been aliased to `latest` in .bashrc, so use `latest discord` to update Discord
       gnome.nautilus
       gimp
       krita
@@ -84,6 +89,10 @@ in
 
       v = "vim";
       rm = "trash-put";
+
+      # Install latest version of package in local environment
+      # config.allowUnfree seems to not apply to nix-env, so is provided explicitly
+      latest = "NIXPKGS_ALLOW_UNFREE=1 nix-env -f https://github.com/NixOS/nixpkgs/archive/master.tar.gz -iA";
     };
   };
 }