Transaction now supports pub sub clients

Added

• Support for PubSub.
• Setter/getter for pubsub client.
• trigger_event! to push messages to pubsub client.
• Unit tests for pubsub integration.

Changed

• finish! params. (Takes status, clear and data)

Support ruby version >= 2.4

• Add support for ruby >= 2.4
• Update rake to 12.3
• Add dependency badge, code climate badge.

Initial Release

[0.1.3] - 2019-07-18

Added

• Codeclimate configuration.
• Rubocop autofixes and exclude patterns.
• Enable test coverage.