custom" config file in a group named "foo".
Config::load('custom', 'foo');

// update some config item
Config::set('foo.key', $value);

// save the updated config group 'foo' (note: it will save everything in that group!)
Config::save('custom', 'foo');

// save the updated config group 'bar' to config file 'custom' in the module 'foo'
Config::save('foo::custom', 'bar');

// save the updated config group 'bar' to memcached using the identifier 'custom'
Config::save('custom.memcached', 'bar');</code></pre>
		