add nixpkgs-unstable

krebs/nixpkgs-unstable.json

@@ -0,0 +1,7 @@
+{
+  "url": "https://github.com/NixOS/nixpkgs-channels",
+  "rev": "d484f2b7fc0834a068e8ace851faa449a03963f5",
+  "date": "2019-09-20T22:58:43+02:00",
+  "sha256": "0jk93ikryi2hqc30l2n5i4vlgmklrlzb8cf7b3sg1q3k70q344jn",
+  "fetchSubmodules": false
+}

krebs/update-nixpkgs-unstable.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+dir=$(dirname $0)
+oldrev=$(cat $dir/nixpkgs-unstable.json | jq -r .rev | sed 's/\(.\{7\}\).*/\1/')
+nix-shell -p nix-prefetch-git --run 'nix-prefetch-git \
+  --url https://github.com/NixOS/nixpkgs-channels \
+  --rev refs/heads/nixos-unstable' \
+> $dir/nixpkgs-unstable.json
+newrev=$(cat $dir/nixpkgs-unstable.json | jq -r .rev | sed 's/\(.\{7\}\).*/\1/')
+git commit $dir/nixpkgs.json -m "nixpkgs-unstable: $oldrev -> $newrev"