How to customize Leave app to add substitute employee?
We want to customize Leaves module in Odoo 12.
a) When an Employee create a Leave Request, there should be option to select Substitute Employee.
b) When submitting leave request, First it should go to Substitute Employee for Approval in the workflow, then to his manager, then HR manager, that is already in Leave workflow. How to add substitute employee in the Workflow?
c) Substitute employee should receive email from the workflow, click the button in email and approve in Odoo?
Please guide how to do customization, what could the suggested steps to get the solution,
1) Creating a new App and inherent from hr_holidays and adding substitute employee field?
2) Which view to update to show substitute employee?
3) How to customize the Leave workflow and send email to substitute employee and adding his approval?