Docker support

[pnmcosta]

Please note this PR includes all the changes on #29 as well, so you can accept only this one if you're ok with the other one.

More info about the docker integration here: https://github.com/pnmcosta/saas-boilerplate/wiki/Changes-on-docker-support-branch but the readme as also been updated.

[tima101]

@pnmcosta I tested tests and starting app with a new way of passing env vars - works properly.

Haven't tested Docker but will merge anyway, will test after merging.

Thanks for making a lot of improvements, I think they are all great.

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I will update sections related to env vars and Docker in project's README.

[pnmcosta]

awesome, glad I could help and learn at the same time :)

I've got a microsoft graph oauth implementation on the oauth-azure (named it wrong!) but it does change the mongo database schema for users, as it now encrypts the tokens using https://github.com/wheresvic/mongoose-field-encryption so it maybe a breaking change to those that already use the boilerplate.

I'll write up some more details on the wiki, and if you'd like I can also PR it.

[tima101]

@pnmcosta We already have two ways to authenticate. I suggest just keeping current two: google oauth and passwordless.

[pnmcosta]

Yup, got it, I'll keep the branch cause I'll need it for something i'm working on.