Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -14,10 +14,11 @@ Each commit must have a name that starts with the following elements:
 * `[UPDF]` For a feature update
 * `[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
+* `[CLEAN]` For refactoring or deleting unnecessary comments
+* `[COMMENT]` For adding comment
+* `[TEST]` For adding or update of unit tests
 
 
 ### Branch name