Need Customization in Fees Module of Ruby on Rails Application Fedena

Hello, I need a very little change in the Fee of Fedena School Management System a Ruby on Rails Application. at Current: We create a Fee Category the Fee Particulars for that Category and Fee Discounts for Particulars of that Category then Schedule a Fee Collection with Due Date if We want to check Fee Defaulters (Student didnt Paid yet) we can check by Fee Collection due date I want to skip this Schedule a Fee Collection and add a field Due Date in Fee Particulars and then When we want to check Fee Defaulters we can check by this Fee Particulars Due Date.