Introducing the RSS_creator gem

require 'rss_creator'

rss = RSScreator.new

rss.title = 'The Edinburgh Weather forecast feed'
rss.desc = 'Weather data fetched from forecast.io'

item = {
  title: 'Tuesday: Drizzle in the morning', 
  link: 'http://www.yourwebsite.com/2015/oct/24/#8am',
  description: 'In the east of Edinburgh, drizzle is expected in the ' + \
                      'morning with a minimum temperature of 6 degrees Celcius'
}
rss.add item
rss.save 'feed.rss'

Output:

<?xml version='1.0' encoding='UTF-8'?>
<rss version='2.0'>
  <channel>
    <title>The Edinburgh Weather forecast feed</title>
    <description>Weather data fetched from forecast.io</description>
    <item>
      <title>Tuesday: Drizzle in the morning</title>
      <description>In the east of Edinburgh, drizzle is expected in the morning 
with a minimum temperature of 6 degrees Celcius</description>
      <link>http://www.yourwebsite.com/2015/oct/24/#8am</link>
      <pubDate>Sat, 24 Oct 2015 22:40:10 +0100</pubDate>
    </item>
  </channel>
</rss>

Resources