Many to Many, 1 to Many, Many to 1 Relation in Custom fields

Use case : It is for project management, where manager can enter modules and assign to some developers to test these functionalities. Manager can assign many modules to one developer(user) or one module to many users likewise.

This is almost similar to Account Team for an Account.

Here my object name is Module__c

Fields are,

Enter_Modules__c(multi-line text box)

Assign_To__c(multi-line text box in order to choose many users)