Extracts all article links and initiates crawling them.

        :param obj response: The scrapy response

def rss_parse(self, response):
        """
        Extracts all article links and initiates crawling them.

        :param obj response: The scrapy response
        """
        for item in response.xpath('//item'):
            for url in item.xpath('link/text()').extract():
                yield scrapy.Request(url, lambda resp: self.article_parse(
                    resp, item.xpath('title/text()').extract()[0]))