merge builder and rss into one guide

views/rss_feed_with_builder.md

@@ -0,0 +1,43 @@
+RSS Feed
+--------
+
+The [builder](https://github.com/jimweirich/builder) gem used for creating XML
+markup is required in this recipe.
+
+Let's first write our basic app to begin with:
+
+```ruby
+require 'sinatra'
+require 'builder' # dont for get this!
+
+get '/rss' do
+  @posts = # ... find posts
+  builder :rss
+end
+```
+
+Then, assuming that your site url is `http://liftoff.msfc.nasa.gov/`, we will
+set up our view at `views/rss.builder`:
+
+```ruby
+xml.instruct! :xml, :version => '1.0'
+xml.rss :version => "2.0" do
+  xml.channel do
+    xml.title "Liftoff News"
+    xml.description "Liftoff to Space Exploration."
+    xml.link "http://liftoff.msfc.nasa.gov/"
+
+    @posts.each do |post|
+      xml.item do
+        xml.title post.title
+        xml.link "http://liftoff.msfc.nasa.gov/posts/#{post.id}"
+        xml.description post.body
+        xml.pubDate Time.parse(post.created_at.to_s).rfc822()
+        xml.guid "http://liftoff.msfc.nasa.gov/posts/#{post.id}"
+      end
+    end
+  end
+end
+```
+
+This will render the RSS inline, directly from the handler.