Add a configure method to the class

lib/paapi.rb

@@ -8,4 +8,19 @@ require 'paapi/response'
 module Paapi
   class Error < StandardError; end
   class NotImplemented < StandardError; end
+
+  class << self
+    attr_accessor :access_key,
+                  :secret_key,
+                  :partner_tag,
+                  :partner_type,
+                  :marketplace,
+                  :test_mode
+
+    def configure
+      yield self
+      true
+    end
+    alias_method :config, :configure
+  end
 end