add a convenience script for maintainers

download-from-github.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# (Note: This isn't used in the build at all, just a convenience script to
+# avoid having to copy-paste the download link from GitHub each update).
+
+if [ "$1" == "" ]; then
+  echo 'usage: ./download-from-github <elixir version>'
+  exit 1
+fi
+
+wget -O "elixir-$1.tar.gz" \
+  "https://github.com/elixir-lang/elixir/archive/v$1.tar.gz"