Found garden snail, kind of want to keep it?

Hello. Well my mom was out mowing the lawn when she almost ran over a little tiny baby snail. (About half-size of a pea.) I find it really cute and want to keep it. I need to know what it eats, what kind of habitat it could live in and how big (I have things from a really small critter keeper to a big 10 gallon tank, of course he surely wouldn't need something that big?) and how long he'll live in captivity, because if he'd just be better off outside I'll just set him back where I found him. He lived not more on the lawn but in a little flowerbed with weeds and grass. (Bug life is in great abundance in there, I have seen spiders, crickets, centipedes, etc. Is there a certain Temperature I Should keep it? Also, one last question. Are they social? Do they need a group of them? Thanks.