如何在rails表格中处理ruby中的日期对象？

<%= @user.created_at.strftime("%Y-%m-%d %H:%M:%S") %>

<%= l @user.created_at %>

<%= distance_of_time_in_words(Time.now, @user.created_at) %>

<%= time_ago_in_words(@user.created_at) %>

<%= date_select :user, :birthday %>

<%= time_select :user, :start_time %>

<%= datetime_select :user, :start_time %>

<%= select_date Date.today, field_name: 'user[birthday]' %>

<%= select_time Time.now, field_name: 'user[start_time]' %>

<%= select_datetime Time.now, field_name: 'user[start_time]' %>