Example OAuth gem usage with Google API

[Aaron Chandler]

Hi,

Would someone direct me to a working example of using the OAuth gem to connect to the Google API (specifically for Analytics)? I have created a service account in the Google API Console and have the private key it generated (.p12 file). How is this key used by the OAuth gem? It is not a simple text file, yet the demonstration of usage in the docs mentions using the "key", as it were a string. Any help would be appreciated. 

Thanks