def addFeed(self, user, session_token, url, title = None, site = None):
		''' anyadir un feed 
		'''
		new = Feed()
		new.rss = url
		
		data = rss.parse(url)
		if site is None:
			try:
				new.site = data.feed.link
			except:
				new.site = ""
			
		if title is None:
			try:
				new.title = data.feed.title
			except:
				new.title = ""
			
		feed_loader = PostgresFeedLoader()
		feed_loader.setCredentials(user, session_token)
		
		feed_loader.save(new)