Check filters after app is initialized

Avoids accessing models that are not loaded yet: `NameError: uninitialized constant Event`

app/helpers/application_helper.rb

@@ -2,6 +2,8 @@
 
 # The core application helper
 module ApplicationHelper
+  IGNORED_FILTERS = %w[user].freeze
+
   # def bootstrap_class_for flash_type
   #   { success: "alert-success", error: "alert-danger", alert: "alert-warning", notice: "alert-info" }[flash_type] || flash_type.to_s
   # end

config/initializers/check_hidden_filters.rb

@@ -0,0 +1,12 @@
+# frozen-string-literal: true
+
+Rails.configuration.after_initialize do
+  # check the filter lists for correctness
+  if TeSS::Config.solr_enabled && TeSS::Config.solr_facets.present?
+    TeSS::Config.solr_facets.each_pair do |name, keys|
+      unknown_facets = Set.new(keys) - name.classify.constantize.facet_keys
+
+      raise "unknown facets defined for #{name}: #{unknown_facets}" if unknown_facets.any?
+    end
+  end
+end