I wrote a guide on automating the launch of WordPress sites through Composer and WP-CLI for Design Bombs:
Bootstrapping WordPress projects with Composer and WP-CLI
Following the method I described in this guide, it literally takes seconds to launch a new WordPress site, making it ideal when we need to launch multiple instances of a site (DEV, STAGING, PROD) or when we produce WordPress sites for clients.
After we have created the database, and set-up the environment variables with its information, we just need to run:
$ composer create-project leoloso/wp-install new_wp_site
...and this script will install the new WordPress site:
The source code for this project is in this repo. Enjoy!