Server time

I added a method to request server time. Let me know what you think.
example mean that it store example data. change it to api_key.rb doesn't have big sens because API_KEY variable will be blank in this situation so it doesn't have real value. This file is using in integration test, and in spec_helper only *.rb file is loaded automaticaly. This mean that *.rb.example will not be loaded which i think it is good.