Improve the README file

Author: williamdes

README.md

@@ -6,6 +6,8 @@
 |8.x.x|![Build docker image](https://github.com/sudo-bot/docker-phpunit/workflows/Build%20docker%20image/badge.svg?branch=8)|
 |9.x.x|![Build docker image](https://github.com/sudo-bot/docker-phpunit/workflows/Build%20docker%20image/badge.svg?branch=9)|
 
-Go to [Doctum](https://github.com/sebastianbergmann/phpunit#readme) at GitHub
+Go to [phpunit](https://github.com/sebastianbergmann/phpunit#readme) at GitHub
 
 You can find the image on [Docker Hub](https://hub.docker.com/r/botsudo/phpunit)
+
+[![Docker Pulls](https://img.shields.io/docker/pulls/botsudo/phpunit.svg)](https://hub.docker.com/r/botsudo/phpunit)