add to allowed upload types

This goes in the functions if you need to allow other file types to upload to the library. The example adds two e-book formats.

// add types to allowed uploads
add_filter('upload_mimes', 'custom_upload_mimes');
function custom_upload_mimes ( $existing_mimes=array() ) {
	// add the file extension to the array
	$existing_mimes['epub'] = 'mime/type';
	$existing_mimes['prc'] = 'mime/type';
    // call the modified list of extensions
	return $existing_mimes;
}