A very basic queue to allow downloading feeds

[humphd]

To get us started, I've taken a crack at writing a basic queue-based producer/consumer app, based on Bull (Bull on GitHub). Nothing in this PR is sacred, and it can all be changed, but I wanted to get us moving forward with a basic prototype people can hack on.

To run this, you need to have Redis installed (we'll need install docs added for Windows/Linux/macOS in other bugs and/or use Docker or something).

Next, you can start the server like so:

npm install
npm start

This will start the server, read the list of feed URLs in feeds.txt (just a few to get us something to test on), and convert them into jobs for the queue.

A worker will start watching for jobs to appear in the queue, and process them. At this point, all it does is download the feed from the URL and dump it to the console:

Enqueuing Job - https://neilong31.wordpress.com/feed/
Enqueuing Job - http://ajhooper.blogspot.com/feeds/posts/default
Enqueuing Job - http://ljubomirgorscak.blogspot.com/feeds/posts/default
Enqueuing Job - http://nashutzu.blogspot.com/feeds/posts/default
Enqueuing Job - http://nadavid.blogspot.com/feeds/posts/default
Enqueuing Job - http://gkrilov.blogspot.com/feeds/posts/default
Enqueuing Job - http://KrazyDre.blogspot.com/feeds/posts/default?alt=rss
Enqueuing Job - http://dcucereavii.blogspot.com/feeds/posts/default?alt=rss
Processing job - https://neilong31.wordpress.com/feed/
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...
Processing job - http://ljubomirgorscak.blogspot.com/feeds/posts/default
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...

Once it processes all the jobs, it will sit and wait for more to arrive. Right now, none will, but we can restart the list after it completes.

Hopefully this will give people something to play with, and get you thinking about how to plug other things into the mix.

I'd like to merge this, but would appreciate a review before I do. Anyone able to do that for me?

[Reza-Rajabi]

Looks great.

[UltimaBGD]

Only thing I'd want to talk about is the dependency ranges, but they would both be non major version updates which would likely not run into newer version problems so it likely doesn't matter much here.