license: Switching license to GPL 3.0

Change-Id: I6b1ceb6fb6498503c4d0ddcab2ea77ffe6ad441b
Refs: #1540
diff --git a/ndn-handle/read-handle.hpp b/ndn-handle/read-handle.hpp
index 1f5af86..9f86c55 100644
--- a/ndn-handle/read-handle.hpp
+++ b/ndn-handle/read-handle.hpp
@@ -1,7 +1,20 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (C) 2014 Regents of the University of California.
- * See COPYING for copyright and distribution information.
+ * Copyright (c) 2014,  Regents of the University of California.
+ *
+ * This file is part of NDN repo-ng (Next generation of NDN repository).
+ * See AUTHORS.md for complete list of repo-ng authors and contributors.
+ *
+ * repo-ng is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * repo-ng is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * repo-ng, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef REPO_NDN_HANDLE_READ_HANDLE_HPP