/**
	 * Post type model name
	 *
	 * @var string
	 */
	protected $model_post_type = 'achievement';

	/**
	 * Object properties
	 *
	 * @var array
	 */
	protected $properties = array(
		'awarded'    => 'string',
		'engagement' => 'absint',
		'related'    => 'absint',
	);

	/**
	 * Retrieve the image source for the achievement.