Add black formatting hook

pre-commit.d/black.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+FILES=$(git diff --cached --name-only --diff-filter=ACM "*.py" | sed 's| |\\ |g')
+
+LINE_LENGTH=90
+
+if [ ! -z "$FILES" ]; then
+    # Format all selected files
+    echo "$FILES" | xargs $HOME/.local/bin/black -l $LINE_LENGTH
+
+    if [ $? -ne 0 ]; then
+        exit 1
+    fi
+
+    # Add back the modified files to staging
+    echo "$FILES" | xargs git add
+fi