Add goworker.Enqueue function (proposal)

This is a proposal to add an Enqueue function based on issue #1 discussion.

There is at least one  issue that I would like to discuss:

_Package scoped getConnectionPool func:_

To be able to use the same Redis connection pool implies to write a package scoped method that will create the pool if needed and return it. This modify the actual code by not allowing Work() func to close de pool at the end. We can still close it but it means we will re-create a pool next time Enqueue() will be called and again, Enqueue should not close the pool either.

Any idea on how to solve this in a better way

It's my first contribution to a Go project and I'm far from an expert with this language, so any guidance is welcome.