Simple Code in Ruby with Mechanize

I need a simple code in Ruby that will log in to the site [login to view URL] with my username, save the cookie, and scrape the data for a specific chart for a year, using each date as a Saturday in that year. For instance, I would need the Billboard 200 data, so the chart would be located at [login to view URL] for January 7th. I'd then need to cycle through 01-14, 01-21, 01-28, etc. If the code can be created so that I could put the dates into a file, or the ruby file, I would input the dates for each year. I just need the code to maintain a login and cycle through the specific dates. Thanks