doc: add explorers in readme

Author: qianbin

README.md

@@ -19,6 +19,7 @@ This is the first implementation written in golang.
 * [Running Thor](#running-thor)
     * [Sub-commands](#sub-commands)
 * [Docker](#docker)
+* [Explorers](#explorers)
 * [Faucet](#testnet-faucet)
 * [RESTful API](#api)
 * [Acknowledgement](#acknowledgement)
@@ -149,6 +150,13 @@ Do not forget `--api-addr 0.0.0.0:8669`, if you want to access RESTful API from
 
 The [Dockerfile](Dockerfile) is designed to build the last release of the source code and will publish docker images to [dockerhub](https://hub.docker.com/r/vechain/thor/) by release, feel free to fork and build Dockerfile for your own purpose.
 
+## Explorers
+
+Awesome explorers from community:
+
+- [VeScan](https://www.vescan.io/)
+- [VeForge](https://explore.veforge.com/) by *Totient Labs*
+
 ## Testnet faucet
 
 ```