Enhancement/Document how to run tests

[c-w]

Resolves #214

[erikamenezes]

Suggestion: Add collectstatic as well?

Also, even though the django tests pass, the CI sometimes breaks due to some style guidelines. So I've found running the tools/ci.sh to be better.

[c-w]

@erikamenezes Thanks for the suggestion. The need to run collectstatic before the tests will be removed as soon as #207 is merged so I wouldn't document this just now.

I'm hesitant to recommend tools/ci.sh as the default test runner since it won't work on Windows. Ideally we'd re-write the bash scripts in Python so that they can be run cross-platform. I can work on porting the tools to Python or even something slightly more complete like using fabfile or invoke. Thoughts @Hironsan?

[Hironsan]

It is better to explain only how to run the basic test. It's executable for any developers.