Sequel-vertica 
A third party adapter to use Vertica through sequel, most of the actual work is done by sequel and the vertica gem.
Usage
The usage is straight forward as any other Sequel adapter, just make sure to require sequel and the sequel-vertica gem.
require 'sequel'
require 'sequel-vertica'
$DB = Sequel.connect('vertica://user:pw@host/database_name')