title: create object from class name as string in ruby
body: <p>I have a model source (name, url, method)
  The program parses the source's url for data. Now I have differen classes for parsing different types of urls: rss, xml, ogdata ...</p>
  
  <p>So I have a common interface</p>
  
  <blockquote>
    <p>new(url) //Parses the url </p>
    
    <p>getTitle() //Get the title of the data</p>
    
    <p>getPrice() //Get the price</p>
  </blockquote>
  
  <p>And I have four classes rss, xml, ogdata. These classes are in seperate files. The idea is to add more classes as I discover different types of pages. I want to initiate the right classes for the url.</p>
  
  <p>method=source.method
  //NOw I want to create a new class of the name specified in method</p>
  
  <p>parser=Rss.new(source.url)//Instead of this
  //Something like
  parser=.new(source.url)</p>