Make event registrations admin readonly

Author: aahnik

src/haps/admin.py

@@ -105,6 +105,12 @@ class EventRegistrationAdmin(admin.ModelAdmin):
         })
     ]
 
+    def has_change_permission(self, request, obj=None):
+        return False
+
+    def has_delete_permission(self, request, obj=None):
+        return False
+
     def has_add_permission(self, request):
         return False