Add script for separate commits for each file updated by black.

Author: adiroiban

admin/black_separate_commits.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+# This is a helper for creating a separate commit for every file that was
+# automatically updated by black.
+#
+# This is designed to be used after black was updated and it needs to
+# change many files at once.
+#
+# To use this script:
+# * Update the black version in .pre-commit-config.yaml
+# * Commit the .pre-commit-config.yaml change
+# * Run `pre-commit run --all`
+# * Run this script.
+#
+for file in $(git diff --name-only)
+do
+    git commit -m "Black auto-update: $file." $file
+done