实训作业迁移问题

db/migrate/20190314080802_create_shixun_student_works.rb

@@ -24,6 +24,8 @@ class CreateShixunStudentWorks < ActiveRecord::Migration
           shixun = work.homework_common.try(:homework_commons_shixuns).try(:shixun)
           user = work.user
           if shixun.present? && user.present?
+            myshixun = Myshixun.where(:user_id => user.id, :shixun_id => shixun.id).first
+            if myshixun.blank?
               # 创建新的myshixun和games
               # fork版本库，如果用户没有同步，则先同步用户
               g = Gitlab.client
@@ -68,6 +70,7 @@ class CreateShixunStudentWorks < ActiveRecord::Migration
                   Game.create!(:challenge_id => challenge.id, :myshixun_id => myshixun.id, :status => status, :user_id => myshixun.user_id,
                                :open_time => Time.now, :identifier => code, :modify_time => challenge.modify_time)
                 end
+              end
               work_score = work.final_score
               work.homework_common.homework_challenge_settings.each do |setting|
                 if work_score > 1