okrb/gatling_gun — pull request #8 by dlackty (2013-12-05 20:12:34+00:00)
Title: Implements categories APIs

Implement several categories API:

* `create_category(category)`
* `add_category(category, name)`
* `remove_category(name, category = nil)`
* `list_categories(category = nil)`

Ref: [SendGrid Categories API Doc](http://sendgrid.com/docs/API_Reference/Marketing_Emails_API/categories.html)