Gategifting
A Gategifter is the opposite of a "Gatekeeper". Instead of not allowing access to a place, object or community; they are overly welcoming. Often obsessed about their interests and hobbies trying to get everyone they can to join.
Oh man Dave won't shut up about bicycles, he finally convinced me to get into biking. Dave is always getting people into his hobbies, he won't stop Gategifting.