Bumping expiration to 30 days

• bumping expiration to 30 days
• fixing specs

Initial support for nested batches

Initial suport for nested batches.

Thanks to:
https://github.com/cybey
https://github.com/darrhiggs

Adds support for Callback#method syntax

Adds support for callback syntax like:

batch.on(:success, 'MyCallback#on_success')

Thanks to https://github.com/cybey

Allows to run on Sidekiq 4

v0.1.1

Version 0.1.1

Initial implementation

v0.1.0

Version 0.1.0

Initial implementation with missing status implementation

0.1.0.pre

Initial implementation - missing status