从查询看，已经得到了正确的记录，为啥 name 显示为 group?

g2=Group.where(:name=>"Geburt")
  Group Load (0.7ms)  SELECT `groups`.* FROM `groups` WHERE `groups`.`name` = 'Geburt'
 => [#<Group id: 1, name: "Geburt", product_id: 1, created_at: "2013-02-21 00:48:46", updated_at: "2013-02-21 00:48:50">] 
1.9.3-p385 :044 > g2
 => [#<Group id: 1, name: "Geburt", product_id: 1, created_at: "2013-02-21 00:48:46", updated_at: "2013-02-21 00:48:50">] 
1.9.3-p385 :045 > g2.name
 => "Group" 

group 的 name 定义。