Upgrade to rails 6 💎 (#11)

- upgraded to rails 6
- fixes various issues

config/initializers/bot.rb

@@ -4,7 +4,7 @@ unless Rails.env.production?
     bot_files.each{ |file| require_dependency file }
   end
 
-  ActionDispatch::Callbacks.to_prepare do
+  ActiveSupport::Reloader.to_prepare do
     bot_reloader.execute_if_updated
   end