fix self course buy

apps/payment/views.py

@@ -46,7 +46,7 @@ class CourseBuyView(TemplateView):
         host = request.scheme + '://' + request.get_host()
         course = Course.objects.get(id=pk)
         if request.user == course.author:
-            messages.error('Вы не можете приобрести свой курс.')
+            messages.error(request, 'Вы не можете приобрести свой курс.')
             return redirect(reverse_lazy('course', args=[course.id]))
         course_payment = CoursePayment.objects.create(
             user=request.user,