Use pytest

[CavalcanteLucas]

Link to task:
Issue #38

How to test:
Run pytest comman, or the script make test in the main directory and check that all tests are passing.
Run make cov and check that browser opens with test reports.

Description of your solution:

• Libs pytest-cov, pytest, pytest-sugar, and pytest-django were installed.
• .coveragerc, and pytest.ini files were created.
• A sample test is introduced.
• Makefile scripts for test and coverage reported are included.
• README.md is updated with testing instructions.