call

# File activerecord/lib/active_record/migration.rb, line 370
      def call(env)
        if connection.supports_migrations?
          mtime = ActiveRecord::Migrator.last_migration.mtime.to_i
          if @last_check < mtime
            ActiveRecord::Migration.check_pending!(connection)
            @last_check = mtime
          end
        end
        @app.call(env)
      end