demo_config_translation module with Configuration Translation example

Hello!

Some time ago I created a module with Configuration Translation support. There is detailed explanation: http://drupal.stackexchange.com/questions/87922/add-multilingual-support-to-drupal-8-hello-world-module/87923#87923
I think drupal8-demo is a good place for it so I suggest pull request with new "demo_config_translation" module. 
What do you think?