Make configuration threadsafe [ch23375] (#73)

* Make config threadsafe

* Update README

* Bump version

README.md

@@ -59,6 +59,8 @@ ChartMogul.account_token = '<Account key goes here>'
 ChartMogul.secret_key = '<Secret key goes here>'
 ```
 
+Configuration is threadsafe and applied only to the current thread.
+
 Test your authentication:
 ```ruby
 ChartMogul::Ping.ping

lib/chartmogul.rb

@@ -77,8 +77,11 @@ module ChartMogul
  class << self
  extend ConfigAttributes
 
+ CONFIG_THREAD_KEY = 'chartmogul_ruby.config'
+
  def config
- @config ||= ChartMogul::Configuration.new
+ Thread.current[CONFIG_THREAD_KEY] = ChartMogul::Configuration.new if Thread.current[CONFIG_THREAD_KEY].nil?
+ Thread.current[CONFIG_THREAD_KEY]
  end
 
  config_accessor :account_token

lib/chartmogul/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module ChartMogul
- VERSION = '1.5.2'
+ VERSION = '1.6.0'
 end