TimeLogControlle的 new 方法中创建 TimeEntry 时传了一堆参数但是 TimeEntry 类 的 initialize 方法好像并没有对参数进行处理，很迷惑，有知道的或者我哪里搞错了可以指点一下吗，不胜感激~

def new
    @time_entry ||= TimeEntry.new(:project => @project, :issue => @issue, :user => User.current, :spent_on => User.current.today)
    @time_entry.safe_attributes = params[:time_entry]
end

def initialize(attributes=nil, *args)
    super
    if new_record? && self.activity.nil?
      if default_activity = TimeEntryActivity.default
        self.activity_id = default_activity.id
      end
      self.hours = nil if hours == 0
    end
 end