如何在Admin :: Records＃show中的活动管理员应用程序NoMethodError中摆脱此错误？

I have installed active admin gem to my rails app. I integrated with my models well. After I login to admin panel and want to view my records it shows this error. This error comes in updating and submitting the button. But internally the file is updated and edited, there is no side effect of this.I have installed active admin gem to my rails a