初学DataMapper，建了以下类：

rubyclass Node
  include DataMapper::Resource

  property :nid,         Serial
  property :title,       String
end

但报错：
~ Table 'NWST.nodes' doesn't exist (code: 1146, sql state: 42S02, query: SELECT nid, title FROM nodes ORDER BY nid, uri: mysql:root@127.0.0.1/NWST?scheme=mysql&user=root&password=&host=127.0.0.1&port=&path=/NWST&query=&fragment=&adapter=mysql)

这是因为表名是node，DM自动改为复数名，如何才能指定表名？