How to create admin, student, principal, teacher from devise because they all have different attributes that's why they are different models? Rails

I want to create school management app so that's why i have created four different models are Admin,Principal,Teacher,student because they have different information so that's why i created them , so how can i create them via single "devise gem" please clear my concept about how to associate them, i have tried to inherit them from user with STI but it only save the user attributes on student model and cant achieve what i want to do, there are other models too but they are associated with these four models and i am stuck at this point only ,so how can i do it any advise and idea . thanks in advance.

Solution

Typically, site users such as Admins, Principals, Teachers and Students have lots of overlapping functionality, and the only true difference between each model is the privileges they have on the site. E.g. an admin might have full access, a teacher will be able to review tests and students have limited access only.

Because most functionality is shared, it would be nice if they have a common model, lets call this User and generate that with Device:

rails generate devise User

Afterwards (or, if you prefer, in the create statement), we add a column role to the User database:

class AddRoleToUsers < ActiveRecord::Migration[7.0]
  def change
    add_column :users, :role, :string, null: false, default: "pending"
  end
end

Thanks to this role, we can limit certain portions of the site, or certain functionality, from the user. On top of that, we don't have to write the same code multiple times!

You could e.g. check a certain role like this:

class User < ApplicationRecord
  
  ROLES = ["pending","admin","principal","teacher","student"]

  
  def admin?(role)
    self.role == "admin"
  end

end

More approaches are possible, e.g. a binary role , or even another table Roles that has a many to many relation with Users, but the example is just to get you started.