added worker system
changed feedzirra gem to feedjira
added fastimage gem for image size detection
on Feed, changed feed_url to url and url to site_url
added exponential backoff logic to feeds in queue_next_parse method
created queueable and parseable concerns for feed and feeditem models to extract common functionality
renamed the image attributes in the feed serializer to prepend image_ rather than append _image
added ready_for_processing scope and fetch_and_process method to feeds and feed items
added some feeds to seeds file
the attributes method on parser instances now scrubs out attributes with nil values
refactored parsers, changed feed item parser to be instantiated independently, without feedjira (for scraping images)
changed the way sequences are specified in factory girl to avoid collisions
added metadata and largest-size image processing
added necessary flags to feeds and feed items to facilitate queueing system
addressed linter issues, fixed broken test
changed to reflect latest spec
Merge pull request #16 from cloudspace/67857670_feed_workers

67857670 feed workers