Add roistat_visit PaymentChildAdmin to read only fields

apps/payment/admin.py

@@ -31,10 +31,12 @@ class PaymentChildAdmin(PolymorphicChildModelAdmin):
         'roistat_visit',
         'created_at',
     )
+
     base_fieldsets = (
         (None, {'fields': ('user', 'amount', 'status', 'data', 'roistat_visit',)}),
     )
-    readonly_fields = ('amount', 'data',)
+
+    readonly_fields = ('amount', 'data', 'roistat_visit',)
 
 
 @admin.register(CoursePayment)