List the names of the top five coins traded on January 1, 2014.
the top five coins refers to cmc_rank< = 5; on January 1, 2014 refers to date = '2014-01-01'
SELECT T1.name FROM coins AS T1 INNER JOIN historical AS T2 ON T1.id = T2.coin_id WHERE T2.date = '2014-01-01' AND T2.cmc_rank <= 5