[AFA-3] Create and configure suite of tests

[ricardopacheco]

Issue number: resolves #3

Summary 🔴

This PR creates and adds an automated test suite with RSpec.

Proposed / Possible solution 🔴

• Suite created following official RSpec conventions and documentation;
• Add editorconfig file;
• Add CI for github;
• Configure environment variables as rails custom configurations;

How to test 👮‍♂️

Considering that the setup is ok, just run the command below:

RAILS_ENV=test bundle exec rspec .

Risks / Impacts 🔴

• None anticipated

Requirements for deployment 🔴

• None anticipated