Add pgx to database driver list

README.md

@@ -243,6 +243,7 @@ Please take a quick gander at the [contribution guidelines](https://github.com/a
     * [go-sql-driver/mysql](https://github.com/go-sql-driver/mysql) - MySQL driver for Go.
     * [go-sqlite3](https://github.com/mattn/go-sqlite3) - SQLite3 driver for go that using database/sql.
     * [gofreetds](https://github.com/minus5/gofreetds) Microsoft MSSQL driver. Go wrapper over [FreeTDS](http://www.freetds.org).
+    * [pgx](https://github.com/jackc/pgx) - PostgreSQL driver supporting features beyond those exposed by database/sql.
     * [pq](https://github.com/lib/pq) - Pure Go Postgres driver for database/sql.
 
 * NoSQL Databases