Simple debug logger

debug_logger.php

<?php
/**
 * Simple debug logger
 *
 * @param $data
 */
function ctrial_write_debug_log( $data ) {
    $debug_file = 'debug.txt';

    // if file already exists append data
    if ( is_writeable( $debug_file ) ) {
        $handle   = fopen( $debug_file, 'a' );
        $new_data = "\n" . implode( " ", $data );
        fwrite( $handle, $new_data );

    } else {
        $handle = fopen( $debug_file, 'w' );
        fwrite( $handle, implode( " ", $data ) );
    }

    fclose( $handle );
}