Last year, Blues City Deli(2438 McNair, 314-773-8225) made Yelp's list of the top 100 places to eat in the U.S. But this year, the beloved Benton Park sandwich shop did one better — it earned a slot in the top 10. Score!Yelp's annual list is generated by its users, but it's not as simple as racking up a five-star rating.…