Write automated tests

[fgmacedo]

Ideas on how to test?

Tests should include:

• Tox (multiple Python versions)

[rsalmei]

Hey @fgmacedo, I finally found time to work on this 😕
Anyway, here it is the start of it: #13

I'm thinking about including tox too, but only after dropping support for python 2.7, what do you think?
I thought about migrating the project to support 3.5, 3.6 and 3.7, as well as celery 3.1, 4.0, 4.1 and 4.2!! That would benefit greatly from tox.

Thanks.

[rsalmei]

Well, it's done... 👍

[fgmacedo]

Congrats!