Ruby-trello and Threads: Making requests on behalf of multiple clients is not currently thread-safe, as demonstrated in the gist below (with placeholders for sensitive data).

ruby_trello_demo.rb

include Trello
include Trello::Authorization

Trello::Authorization.const_set :AuthPolicy, OAuthPolicy
OAuthPolicy.consumer_credential = OAuthCredential.new('user_key', 'user_secret')

threads = []
tokens = %w[ not_rosstas_token rosstas_token ]

tokens.each_with_index do |token, i|
  threads << Thread.new(token) do |access_token|
    OAuthPolicy.token = OAuthCredential.new(access_token)
    sleep 1
    member = Trello::Member.find('rossta')
    puts "Thread #{i + 1}: #{member.inspect}"
    puts "Thread #{i + 1}: #{member.boards.map(&:name).inspect}"
  end
end

threads.each { |thread| thread.join }

# The oauth token for the first thread can be overwritten by the second thread, leading to unexpected results