Add rename branch example.

examples/rename-branch.py

@@ -0,0 +1,28 @@
+#!/usr/bin/python3
+
+from dulwich.client import get_transport_and_path_from_url
+from dulwich.objects import ZERO_SHA
+from dulwich.pack import pack_objects_to_data
+
+import argparse
+parser = argparse.ArgumentParser()
+parser.add_argument('url', type=str)
+parser.add_argument('old_ref', type=str)
+parser.add_argument('new_ref', type=str)
+args = parser.parse_args()
+
+client, path = get_transport_and_path_from_url(args.url)
+
+def generate_pack_data(*args, **kwargs):
+    return pack_objects_to_data([])
+
+
+def update_refs(refs):
+    sha = refs[args.old_ref.encode('utf-8')]
+    return {
+        args.old_ref.encode('utf-8'): ZERO_SHA,
+        args.new_ref.encode('utf-8'): sha}
+
+
+client.send_pack(path, update_refs, generate_pack_data)
+print("Renamed %s to %s" % (args.old_ref, args.new_ref))