this bash script will help generating certificate for virtual domain. If you plan to use Docker with a virutal domain, you might need to create certificate that you'll later add on Trusted Root Certificate Authority (Windows certmgr.msc).
You just simply have to make this file executable using chmod +x. Make sure to store it to a path like /usr/local/bin/localcert (you might change the name to what you want).
Note that the file will generate certificate a the pwd (Working Directory). Therefore, you'll consider moving those certificate to a directory where you store your certificates.