Adds ability to extend built-in workflow models.

Adds connection and queue properties to Activity and Workflow classes to control the options for the underlying queued jobs.

Adds Queries.

Adds concurrent activities (fan-out/fan-in).

Fixes timing issue with signals that are sent within microseconds of creating the workflow. This wasn’t reported by a user but instead was found with the new benchmarking framework that will be published soon.

Add nullable to created_at timestamps.

Add index.

Adds deterministic WorkflowStub::now() helper to get the current time.

Fixes the issue where workflow updated_at microseconds are getting saved.

This release has a breaking change for activities. Instead of $this->model inside activities, it is now $this->storedWorkflow. However, it is recommended to use the new $this->workflowId() helper inside of activities to get the workflow ID instead of accessing the stored workflow directly.

Workflows will now log exceptions to a table. This is added so that the upcoming Waterline UI will be more useful for debugging. The previous migrations should be rolled back before publishing the latest versions. They are not backwards compatible. The migrations and API in general should not be expected to be stable until the first minor release 0.1.0.