Update rubocop, add appraisal gem

spec/integration_helper.rb

@@ -27,7 +27,7 @@ end
 Rails.application.initialize!
 
 # # Controllers
-%w(default other named).each do |bot_name|
+%w[default other named].each do |bot_name|
   controller = Class.new(Telegram::Bot::UpdatesController) do
     define_method :start do |*|
       respond_with :message, text: "from #{bot_name}"