Raise an error on page load if there are pending migrations on dev env

config/environments/development.rb

@@ -16,6 +16,9 @@ Rails.application.configure do
   # Print deprecation notices to the Rails logger
   config.active_support.deprecation = :log
+  # Raise an error on page load if there are pending migrations
+  config.active_record.migration_error = :page_load
+
   # Only use best-standards-support built into browsers
   config.action_dispatch.best_standards_support = :builtin