Idea: show method signature on web UI

[rainerborene]

The current dashboard already shows the parameter values.

But it would be cool to show the method signature of the worker.

Something along these lines:

EngageWorker.instance_method(:perform).parameters # [[:req, :user_id], [:req, :tag_id], [:rest, :args]]

Or even better: a simple abstraction to show custom fields on the job info page.