1. Pull mysql docker image and run it
docker run --name wordpressdb -e MYSQL_ROOT_PASSWORD=password -e MYSQL_DATABASE=wordpress -d mysql

2. Pull wordpress docker image

docker pull wordpress

3. Run the workdpress container and connect it to the mysql running container 

docker run -e WORDPRESS_DB_PASSWORD=password -d --name wordpress --link wordpressdb:mysql wordpress

Now check the container's address 

docker inspect wordpress | grep -i "IPAddress\":"

Done