Add controller, routes, and templates for other error pages

app/controllers/errors_controller.rb

@@ -0,0 +1,25 @@
+class ErrorsController < ApplicationController
+  require_untenanted_access
+
+  layout "error"
+
+  def bad_request
+    render status: :bad_request
+  end
+
+  def not_found
+    render status: :not_found
+  end
+
+  def not_acceptable
+    render status: :not_acceptable
+  end
+
+  def unprocessable_entity
+    render status: :unprocessable_entity
+  end
+
+  def internal_server_error
+    render status: :internal_server_error
+  end
+end