How to add id if there's custom validation rule when updating the record in Laravel?

How to add id in stud_num just like in email and username? the codes found in User Controller.

public function update(Request $request, $id)
    {
        $this->validate($request, [
            'first_name' => 'required|max:255|regex:/^([^0-9]*)$/',
            'middle_name' => 'nullable|max:255|regex:/^([^0-9]*)$/',
            'last_name' => 'required|max:255|regex:/^([^0-9]*)$/',
            'contact' => ['required', 'regex:/^(09|\+639)\d{9}$/'],
            'course' => 'required',
            'role_as' => 'required',
            'stud_num' => ['required', 'unique:users,stud_num', 'max:15', new StrMustContain('TG')],
            'username' => 'required|alpha_dash|unique:users,username,' . $id,
            'email' => 'required|email:rfc,dns|unique:users,email,' . $id
        ]);
                
        // codes for update    
    }

>Solution :

Just add id like email and username.

'stud_num' => ['required', 'unique:users,stud_num,'.$id, 'max:15', new StrMustContain('TG')]