app.rb

require 'faraday'
require 'json'
unregged = []
threads = []

data = Faraday.get("url_to_text_goes_here").body
data.each_line do |element|
  puts element
  threads << Thread.new {
    url = "http://pokemonshowdown.com/users/#{element.strip}.json"
    data = JSON.parse(Faraday.get(url).body)
    if data['registertime'] == 0
      unregged << element[1]
    end
  }
end

threads.map(&:join)
puts "unregged is #{unregged}"