Add credentials files

[fernandascovino]

Closes #22 (finally)

You need to change to your infos on credentials.config file - and please add it on readme :)

[JoaoCarabetta]

I am thinking about the first user.

Them will not have a credentials file set up, so it'd be interesting if them could persist their information.

What do you think?

[fernandascovino]

I created a new branch for this