Fetch username of person assigned to GitHub pull request

assigned_to_pullrequest.rb

require 'json'
require 'open-uri'

user = 'GITHUB_USERNAME'
pass = 'GITHUB_PASSWORD'
repo = 'user/repo'

pulls = JSON.parse(open("https://api.github.com/repos/#{repo}/pulls", :http_basic_authentication => [user, pass]).read)

pulls.each do |pull| 
  issue = JSON.parse(open("https://api.github.com/repos/#{repo}/issues/#{pull['number']}", :http_basic_authentication => [user, pass]).read)
  if issue['assignee'].nil?
    message = "is not assigned to anyone yet"
  else
    message = "is assigned to #{issue['assignee']['login']}"
  end
  puts "##{pull['number']} ('#{pull['title']}') #{message}"
end