Read my two articles about building custom WordPress solution and deploying it to Azure App Service at Azure Blogs
Part 1
Part 2
docker run -e DB_ENV_HOST=[your mysql db url]:[your mysql port number] -e DB_ENV_USER=[your mysql db user name] -e DB_ENV_PASSWORD=[your mysql db password] -e DB_ENV_NAME=[your mysql database name] -p 5000:80 -d [your docker image name]