$config['cache']['backend'] = 'Apc';
$config['cache']['backendOptions'] = array();
$config['cache'] = array(
'enabled' => true,
'frontend' => 'Core',
'frontendOptions' => array(
'caching' => true,
'automatic_serialization' => false,
'cache_id_prefix' => 'folksy_',
'lifetime' => 18000
)...