+ $configTable = $schema->getTable($this->getTable('config'));
+
+ $this->skipIf($configTable->hasColumn('action_mark_as_read'), 'It seems that you already played this migration.');
+
+ $configTable->addColumn('action_mark_as_read', 'integer', [
+ 'default' => 0,
+ 'notnull' => false,
+ ]);