Add new md file WORKFLOW
Add new md file WORKFLOW

  - this .md contains aditional information to CONTRIBUTING.md,
  showing how to create a new branch, rebase with master, commit
  and push to remote, opening a pull request. In order to have a
  defined workflow with git branches, avoiding a master without a
  good history, I added this suggestion.

TWtablero/tablero,giovaneliberato/tablero,giovaneliberato/tablero,TWtablero/tablero,TWtablero/tablero,giovaneliberato/tablero,TWtablero/tablero,giovaneliberato/tablero