Function to add an event listener

Function to add an event listener

on(jug, event, func, ...)

Arguments

jug	the jug instance
event	the event to bind to (one of start, finish or error)
func	the function to pass the req, res, err and (if error event) the err_msg to
...	extra arguments to pass to the listener function

See also

post, put, delete, use, ws