Refactor: extract method purge_existing_data
Refactor: extract method create_channel
Refactor: extract method RssLoader#create_item
Refactor: rename block variable item to rss_item
Refactor: change method param from rss_data to rss_channel
Refactor: extract method RssLoader#create_items
Refactor: change multi-line do block to inline
Refactor: extract method RssLoader#load_data_from_rss_feed
Add a TODO, fix some whitespace