Run Mail-in-a-Box in the same droplet as my website and API
I have a domain registered with Godaddy called example.it
I am running a REST API and my basic html website on the same droplet.
Now I want to run our own mail server, I read the article on https://www.digitalocean.com/community/tutorials/how-to-run-your-own-mail-server-with-mail-in-a-box-on-ubuntu-14-04 but this seems to be only to run a whole droplet as a mail server (and not a subdomain).
How can I achieve this to run the Mail-in-a-box on the same droplet without problems for the API and website?
Thanks in advance for any help