How to contribute to this project

## Content
Introduced documentation to start contributing to the project. Any collaborators will follow a _brief guide_ to interact with the project. The file of contribution _CONTRIBUTING.md_, has been enriched with the information of **maintainer** of the project.

## Work flow changes
If the **maintainer decide to merge** this request, he will receive e-mails directly from any _committer candidates_. If this is not acceptable, it will be necessary to define an official communication channel to receive requests for those interested in working directly on this repository as maintainers or committers.

In the document of contribution is also specified in which way _standard users_ (those that are not committers or maintainers), may operate to contribute to the project.