rake流产!ActiveRecord:::StatementInvalid: SQLite3::SQLException:没有这样的表:耙子自动化难以工作

I'm working on making a to-do list application and I'm trying to implement a feature where a to-do list item will automatically be deleted after 7 days if it never was completed within that time period. I'm trying to use rake automation with the help of the 'whenever' gem however I receive the following error:I'm working on making a to-do list application