Google analytics behaviour API Throws Error

Google API V3 To get Behaviour Overview Data returns Error

ref: http://ift.tt/2w757Wk

Google::Apis::ClientError: dailyLimitExceededUnreg: Daily Limit for Unauthenticated Use Exceeded. Continued use requires signup.

Unable to find any reference/code to get GA Data in Ruby.

How to set Authentication and create Request. I have secret Key and other Credentials with me.