Update.I added the hreflang urls in sitemap and did what google instructs but their instructions are wrong. The sitemap doesnt validate as the xhtml:link tag does not exist in given namespace. Even their own example is invalid. Use a sitemap validator to test it by your self.
xmlns:xhtml="http://www.w3.org/1999/xhtml"
ROR vs XML sitemap:ROR sitemaps is an extensions of RSS feeds (which are also XML based)However, no major search engines supports ROR sitemaps (they do support RSS parts however) sitemap.xml is the usual and common sitemap for your site that includes links to all the inner pages of your site. whereas ror.xml is "Resource of Resources" describes any object of your content in a generic fashion, so any search engine can better understand that content and include more details about your site such as products, navigational menu items, , etc. many will use ror to put in details about particular products however be careful not to flag up duplicate content filters with the orginal product page.