We don't have an official addition process. You can send us a message and request a coin and we add your suggestion to our discovery list. This discovery list allows us to look into the coin and see if it is a good fit. We will never assure that we can add a new coin as we get dozens of requests a day for coin additions.
We do announce all new additions on our social media outlets and our newsletter. Connect below to stay up-to-date with these releases:
Newsletter Sign-up: http://eepurl.com/bdbzO1