implement containLetters function, given two words, returns true if all the letters of the first word are contained in the second.

containLetters

    public function containLetters(string $firstWord, string $secondWord)
    {
        $result = array();
        $inc = 0;
        foreach (str_split($firstWord) as $firstSplit)
        {
            foreach (str_split($secondWord) as $secondSplit)
            {
                if (strtolower($firstSplit) == strtolower($secondSplit))
                {
                    $result[$inc] = true;
                }
                else
                {
                    $result[$inc] = false;
                }
            }
            $inc++;
        }

        foreach ($result as $final)
        {
            if ($final == false)
            {
                return false;
            }
        }

        return true;
    }