add pgx to top level docs

Author: dzbee

.github/ISSUE_TEMPLATE/bug_report.md

@@ -25,7 +25,7 @@ e.g. s3, github, go-bindata, gcs, file
 Obtained by running: `migrate -help`
 
 **Loaded Database Drivers**
-e.g. spanner, stub, clickhouse, cockroachdb, crdb-postgres, postgres, postgresql, redshift, cassandra, cockroach, mysql
+e.g. spanner, stub, clickhouse, cockroachdb, crdb-postgres, postgres, postgresql, pgx, redshift, cassandra, cockroach, mysql
 Obtained by running: `migrate -help`
 
 **Go Version**

README.md

@@ -1,3 +1,23 @@
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+**Table of Contents**  *generated with [DocToc](https://github.com/thlorenz/doctoc)*
+
+- [migrate](#migrate)
+  - [Databases](#databases)
+    - [Database URLs](#database-urls)
+  - [Migration Sources](#migration-sources)
+  - [CLI usage](#cli-usage)
+    - [Basic usage](#basic-usage)
+    - [Docker usage](#docker-usage)
+  - [Use in your Go project](#use-in-your-go-project)
+  - [Getting started](#getting-started)
+  - [Tutorials](#tutorials)
+  - [Migration files](#migration-files)
+  - [Versions](#versions)
+  - [Development and Contributing](#development-and-contributing)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
 [![CircleCI - Build Status](https://img.shields.io/circleci/build/github/golang-migrate/migrate/master)](https://circleci.com/gh/golang-migrate/migrate)
 [![GoDoc](https://godoc.org/github.com/golang-migrate/migrate?status.svg)](https://godoc.org/github.com/golang-migrate/migrate)
 [![Coverage Status](https://img.shields.io/coveralls/github/golang-migrate/migrate/master.svg)](https://coveralls.io/github/golang-migrate/migrate?branch=master)
@@ -24,6 +44,7 @@ Forked from [mattes/migrate](https://github.com/mattes/migrate)
 Database drivers run migrations. [Add a new database?](database/driver.go)
 
 * [PostgreSQL](database/postgres)
+* [PGX](database/pgx)
 * [Redshift](database/redshift)
 * [Ql](database/ql)
 * [Cassandra](database/cassandra)