Fix upgrade in progress page

Author: dutow

config/application.rb

@@ -17,6 +17,6 @@ class Application < Rails::Application
     config.autoload_lib(ignore: %w[assets tasks])
 
     require_relative "../app/middleware/pending_migration_catcher"
-    config.middleware.insert_before ActionDispatch::ShowExceptions, PendingMigrationCatcher
+    config.middleware.insert_before 0, PendingMigrationCatcher
   end
 end