Fixes a bug with diffInMonths for DateTime/Carbon

AppDate.php

<?php
use Carbon\Carbon;

/**
 * This fixes the bug in DateTime with diffInMonths!
 * See this bugreport: https://github.com/briannesbitt/Carbon/issues/344
 */
class AppDate extends Carbon
{
    /**
     * Get the difference in months
     *
     * @param \Carbon\Carbon|null $dt
     * @param bool                $abs Get the absolute of the difference
     *
     * @return int
     */
    public function diffInMonths(Carbon $dt = null, $abs = true)
    {
        $dt = $dt ?: static::now($this->getTimezone());

        $months = 0;
        if ($this->eq($dt)) {
            return 0;
        } else if ($this->lt($dt)) {
            $diff_date = $this->copy();
            while ($diff_date->lt($dt)) {
                $months++;
                $diff_date->addMonth();
            }
            return $months;
        } else {
            $dt = $dt->copy();
            while ($dt->lt($this)) {
                $months++;
                $dt->addMonth();
            }
            return $months;
        }
    }
}

thanks a lot. As I've found a bug in php 5.6 with data_diff, I use now Carbon with your patch.