Add pre-commit hook (#13)

Co-authored-by: Antonio Andelic <antonio.andelic@memgraph.io>

tools/git-clang-format

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+import re
+import sys
+import subprocess
+
+# Run this script through arc lint
+
+MESSAGE = "Wrong formatting!"
+
+data = subprocess.run(
+    ["clang-format", "--output-replacements-xml", sys.argv[1]],
+    stdout=subprocess.PIPE, check=True).stdout.decode(
+        "utf-8").strip().split("\n")
+has_error = False
+for row in data:
+    match = re.match(
+        r"^<replacement offset='([0-9]+)' length='([0-9]+)'>", row)
+    if match:
+        has_error = True
+        offset = int(match.group(1)) + int(match.group(2))
+        print("warning:{}:{}".format(offset, MESSAGE))
+
+sys.exit(1 if has_error else 0)