Write documentation for the "tarefas" example

[abstratt]

Expand the readme.md file under pt/tarefas with instructions (in Portuguese) that explain what element in the tarefas.tuml file supports what feature in the corresponding UI (here, for the test user, but adjust for your own user).

Please follow the documentation for Cloudfier in http://doc.cloudfier.com

Please report bugs in Cloudfier itself to http://github.com/abstratt/cloudfier.

Please ask any questions you have about Cloudfier here: https://cloudfier.uservoice.com

Any questions about this assignment, please ask them here.

[abstratt]

@IrrelevantIdentity This issue is for you. As soon as you accept the invite, I will assign it to you.