title: Caching RSS entries with thumbnails using Core Data
body: <p>I've implemented a simple RSS reader which shows title and date and also displays a thumbnail for each entry. </p>
  
  <p>Now I want to implement caching in such a way that the last ten entries are saved on disk (including the images). I have little experience with Core Data and I'm wondering if it's the best solution for my problem. </p>
  
  <p>Also, I'm relatively new to the MVC design pattern and I'd like to know what's the best way to design such a system. Right now my app has a <code>RSSEntry</code> class which stores <code>title</code>, <code>date</code> and <code>thumbURL</code> and represents the model. A class named <code>RSSManager</code> parses the feed and tells its delegate that it's finished parsing, providing an <code>NSArray</code> of <code>RSSEntry</code> instances. Then there's the view controller, a simple <code>UITableViewController</code>, which displays all this stuff in a tableview and also starts an asynchronous download using the <code>imageURL</code> from <code>RSSEntry</code>. When the download is finished, it asks the tableview to reload the respective rows so that the cell's activity indicator is stopped and the image is displayed.  </p>
  
  <p>Given this scenario, what's the best place to implement caching? I guess I need to save each image in the documents directory and then store the file's path, but I'm not sure what's the best way to design this. I want to avoid messy code and perhaps there's a known pattern to achieve this kind of stuff.</p>