add google analyticis account with gem

I added [gem 'google-analytics-rails'](https://github.com/bgarret/google-analytics-rails) to add usergroup with obvious objective to Google Analytics. 

If the choice of this gem is wrong let me know to discuss the reasons. :worried:

Regards to all members of team. :v:

btw, you are free of give me feedback about the change and my style english write, will be very helpful :blush: