Added sample file for git hook

scripts/pre-commit.sample

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# Copy this file to .git/hooks
+
+# Run clang-format before commiting
+files=$(git diff --cached --name-only --diff-filter=ACM | grep -E '\.(cpp|hpp)$')
+[ -z "$files" ] && exit 0
+clang-format -i $files
+git add $files