fix bug

config/initializers/new_features.rb

@@ -4,7 +4,7 @@ Rails.application.configure do
   config.x.email_default_domain = ENV.fetch('EMAIL_DEFAULT_DOMAIN') { '???.edu.cn' }
   config.x.tree_address = ENV.fetch('TREE_ADDRESS') {''}
   config.x.anon_tag = ENV.fetch('ANON_TAG') {'[mask]'}
-  config.x.anon_acc = ENV.fetch('ANON_ACC') {''}
-  config.x.anon_namelist = ENV.fetch('ANON_NAME_LIST') {''}
+  config.x.anon_acc = ENV.fetch('ANON_ACC') {nil}
+  config.x.anon_namelist = ENV.fetch('ANON_NAME_LIST') {nil}
 end