This library does not set a custom user agent

[Ironholds]

My ruby-fu is weak, but this line suggests the gem is just reporting as Ruby/version.

This is not compliant with our API etiquette guidelines or expectations. Please provide an informative default user agent that contains a URL to this project, and (for additional cookies) offer users the ability to append their own agent for their project-specific querying.

[potatodiet]

Now that #30 has been merged, I think this issue could be closed.