Add colours pallete to WordPress visual editor

function ns_mce4_options($init) {

    $custom_colours = '
        "3366FF", "Color 1 name",
        "CCFFCC", "Color 2 name",
        "FFFF00", "Color 3 name",
        "99CC00", "Color 4 name",
        "FF0000", "Color 5 name",
        "FF99CC", "Color 6 name",
        "CCFFFF", "Color 7 name"
    ';

    // build colour grid default+custom colors
    $init['textcolor_map'] = '['.$custom_colours.']';

    // change the number of rows in the grid if the number of colors changes
    // 8 swatches per row
    $init['textcolor_rows'] = 1;

    return $init;
}
add_filter('tiny_mce_before_init', 'ns_mce4_options');