我的用户每个人都分配了一个组。如果管理员删除了他们所在的组，我需要将它们移至无法删除的最基本的组“成员”。
现在我知道该方法有效并且路由和控制器但是因为起初我按顺序从控制器调用方法 moveUsers：
user = User.find(id)
user.moveUsers
user.delete
但是，我想将其分开并保持控制器的简约，即：Rails3 方式？
控制器方法：
def destroy
group = Group.find(params[:id])
if group.delete
redirect_to groups_url, :notice => "Group deleted."
else
redirect_to :back, :notice => "Cannot delete group."
end
end
模型：
class Group < ActiveRecord::Base
before_destroy :moveUsers
validates :title, :presence => :true, :uniqueness => true
has_many :user
# Get the number of users associated with the group & title
def getUserCount
return User.where(:group_id => self.id).length
end
# If group is deleted move all of its users
# to core group: Members (id = 1)
private
def moveUsers
users = User.where(:group_id => self.id)
users.each do |user|
user.group_id = 1
user.save
end
end
end