atomplayground.rb

#!/usr/bin/env ruby

require 'rubygems'

# you can get this from the 'atom-tools' gem
require 'atom/service'

service = Atom::Service.new "http://downloadr.local/sites"
collection = service.workspaces.first.collections.first
puts collection.feed.entries.inspect

# publish with atom
# I'm going to assume you are going to change this to something else.
guts = IO.read("file.png")
s = collection.post_media! guts, "application/octet-stream", "file.png"

# check the collection feed
collection.feed.update!
puts collection.inspect
puts collection.feed.entries.inspect