Add support for other queue backends

[mauricioabreu]

Is it worth to add support for other backends? It could be achieved using go interfaces.
We could start with redis, writing a code that is easy to use different queue vendors.

• Test current SQS backend
• Implement a new backend like redis

[marceloboeira]

👍 We should probably improve the current one, maybe having some good tests, and then start to try out redis. But, since redis is easier to test, since we can run with docker, maybe we try out redis as the first adapter.

[mauricioabreu]

👍 Good idea! I just started to write some tests.

[marceloboeira]

Awesome, once we have that in place, we should start nailing the whole end-to-end exp. (maybe integration/performance tests).

[marceloboeira]

Working on it #7