Create how to contribute guideline

[luizfilipe]

• The guideline must be in CONTRIBUTING.md.
• The guideline must contain all cycle of development.
• The guideline must contain patterns to develop in theis repository

[luizfilipe]

@lrpsantiago any other idea to add to this issue?

[luizfilipe]

The README.md will have to be improved too, after CONTRIBUTING.md has been done.