从题库选择毕设任务时，创建时间应为当前时间

app/controllers/question_banks_controller.rb

@@ -240,7 +240,7 @@ class QuestionBanksController < ApplicationController
     ActiveRecord::Base.transaction do
       new_task = GraduationTask.new
       new_task.attributes = task.attributes.dup.except("id", "course_id", "user_id", "quotes", "graduation_task_id",
-                                                       "course_list_id", "gtask_bank_id")
+                                                       "course_list_id", "gtask_bank_id", "created_at", "updated_at")
       new_task.course_id = course.id
       new_task.gtask_bank_id = task.id
       new_task.user_id = current_user.id
@@ -266,7 +266,7 @@ class QuestionBanksController < ApplicationController
     ActiveRecord::Base.transaction do
       new_topic = GraduationTopic.new
       new_topic.attributes = topic.attributes.dup.except("id", "course_id", "user_id", "graduation_topic_id",
-                                                         "course_list_id", "gtopic_bank_id")
+                                                         "course_list_id", "gtopic_bank_id", "created_at", "updated_at")
       new_topic.course_id = course.id
       new_topic.gtopic_bank_id = topic.id
       new_topic.user_id = current_user.id