Implement tests

[ccarruitero]

I think is usefull for any project have tests.

What prefer to use ..

for unit:
unit test | pytest | ?

for integration:
selenium | splinter | easy_integration | ?

[sebasmagri]

For Unit Tests we should stick to Django standard and use unittest.

For Integration tests I only have some experience with Selenium, so we'd probably use that. However unit tests should be priority. We'd probably track integration tests for a future milestone.