inherited

# File activerecord/lib/active_record/migration.rb, line 525
    def self.inherited(subclass) # :nodoc:
      super
      if subclass.superclass == Migration
        raise StandardError, "Directly inheriting from ActiveRecord::Migration is not supported. "            "Please specify the Rails release the migration was written for:\n"            "\n"            "  class #{subclass} < ActiveRecord::Migration[4.2]"
      end
    end