Add TiDB to Databases section

README.md

@@ -204,6 +204,7 @@ Please take a quick gander at the [contribution guidelines](https://github.com/a
 * [influxdb](https://github.com/influxdb/influxdb) - Scalable datastore for metrics, events, and real-time analytics
 * [ledisdb](https://github.com/siddontang/ledisdb) - Ledisdb is a high performance NoSQL like Redis based on LevelDB.
 * [levigo](https://github.com/jmhodges/levigo) - Levigo is a Go wrapper for LevelDB.
+* [tidb](https://github.com/pingcap/tidb) - TiDB is a distributed SQL database. Inspired by the design of Google F1.
 * [tiedot](https://github.com/HouzuoGuo/tiedot) - Your NoSQL database powered by Golang.
 
 *Database tools.*