Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -15,6 +15,7 @@ Each commit must have a name that starts with the following elements:
 * `[UPDC]` For a feature component
 * `[FIX]`  For a bug fix
 * `[CLEAN]` For refactoring or deleting unnecessary comments
+* `[WIP]` For Work in progress. Use it to make a save of your work, or if no flag above match with your commit
 * `[COMMENT]` For adding comment
 * `[DOC]` For new documentation file or update of the documentation