Message him on twitter and ask him to credit you more openly than sticking it in readme at the bottom which most likely is not read by most people. If he doesn'

Message him on twitter and ask him to credit you more openly than sticking it in readme at the bottom which most likely is not read by most people. If he doesn't, reply to this twitter post adding your own comment. Legally, he may be ok if MIT license but ethically, he should credit you more than just sneaking in a readme fine print.