Add Kiba ETL

[thbar]

• http://www.kiba-etl.org & https://github.com/thbar/kiba
• README, copied here:

Lightweight ETL for Ruby
Writing reliable, concise, well-tested & maintainable data-processing code is tricky.
Kiba lets you define and run such high-quality ETL (Extract-Transform-Load) jobs.

• Already used in production environments