Help identify and feed this snake

[Adam165]

I found a tiny snake at the parts store that a lady working there was freaking out over. I think it may be a baby black racer but I don't know. It's about six inches long and about as big around as a pencil at its middle. It's a dark gray color with an almost white belly. I would post a pic but not sure how from my iPhone. Any ideas? Also, what do snakes this small eat? Bugs?