add url link to pre-build binaries

Author: puxxustc

README.md

@@ -4,6 +4,16 @@ Userspace GRE tunnel, designed for OpenVZ servers (require TUN device support).
 
 Checksum, Key, Sequence are not supported.
 
+## Pre-builds ##
+
+Platform  | Architecture | URL
+----------|--------------|----
+GNU/Linux | x86_64       | https://s3.pxx.io/snapshot/gre/gre-x86_64
+     | armv6l       | https://s3.pxx.io/snapshot/gre/gre-armv6l
+     | armv7l       | https://s3.pxx.io/snapshot/gre/gre-armv7l
+     | aarch64      | https://s3.pxx.io/snapshot/gre/gre-aarch64
+
+
 ## Build ##
 
 ```bash
@@ -18,7 +28,7 @@ sudo ./gre <tun dev> remote local
 
 ## License ##
 
-Copyright (C) 2015, Xiaoxiao <i@xiaoxiao.im>
+Copyright (C) 2015 - 2017, Xiaoxiao <i@pxx.io>
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by