Twitter client (broken)

broken_twitter_client.rb

require 'json'
require 'simple_oauth'
require 'excon'
require 'nokogiri'
require_relative 'lib/twitter_creds'

def post_tweet(string)
  authorization_header = SimpleOAuth::Header.new("post",
                                                 "https://api.twitter.com/1.1/statuses/user_timeline.json",
                                                 { :screen_name => "ugly_name",
                                                   :text => string },
                                                 { :consumer_key => API_KEY,
                                                   :consumer_secret => API_SECRET,
                                                   :token => ACCESS_TOKEN,
                                                   :token_secret => ACCESS_TOKEN_SECRET })
  response = Excon.send("post", "https://api.twitter.com/1.1/statuses/user_timeline.json", {
    :query => { :screen_name => "macsplean",
                :text => string },
    :headers => { "Authorization" => authorization_header.to_s }
  })

  puts response.body
  puts response.status
end


if __FILE__ == $0
  post_tweet("asjdmnaskd")
end

Here's what I get when I run this:

max@max-INVALID twitter-client $ ruby scratch.rb
{"errors":[{"message":"Could not authenticate you","code":32}]}
401