Adiconando nova funcionalidade de Adicionar tasks

[MateusPy]

PTOSS4 da matéria de Teste de software

Implementação da funcionalidade de adicionar Tasks, utilizando o TDD para o desenvolvimento dessa funcionalidade.

[CuriousMagpie]

@SabreCat Can you review this? It looks like additions to task functionality.

[negue]

Hey, I'm a bit confused about this function

It not called anywhere (but , it seems to be an additional counter which (should?) be called somewhere?

Or is this PR not ready.

Also tests should be written in english, then everybody can understand / improve / fix them :)