There are many (old) clients available:
- https://github.com/activenetwork/gattica
- https://github.com/tpitale/legato
- https://github.com/vigetlabs/garb
All are abandoned and you should not use them. The Google Analytics API is at v3 and they are all using an earlier version.
Use https://github.com/google/google-api-ruby-client (Google supported).