Update CustomUserAdmin to use date_joined instead of creation_date

tournaments/admin.py

@@ -34,7 +34,7 @@ class CustomUserAdmin(UserAdmin):
     ordering = ['-date_joined']
     raw_id_fields = ['supervisors', 'organizers']
     fieldsets = [
-        (None, {'fields': ['id', 'username', 'email', 'password', 'first_name', 'last_name', 'is_active', 'creation_date']}),
+        (None, {'fields': ['id', 'username', 'email', 'password', 'first_name', 'last_name', 'is_active', 'date_joined']}),
         ('Permissions', {'fields': ['is_staff', 'is_superuser', 'groups', 'user_permissions']}),
         ('Personal Info', {'fields': ['registration_payment_mode', 'clubs', 'country', 'phone', 'licence_id', 'umpire_code']}),
         ('Tournament Settings', {'fields': [