docs: add legacy code note to README

GitOrigin-RevId: aa0f5a2ce6f9e17116c13e943650cc9d38cb0cfe
diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -2,9 +2,14 @@
 App which is used to keep track of the intervals of time that a worker is in the
 workplace in one or several companies.
 
+*** promo
+This project was created in 2019 and contains legacy code that does not reflect
+my current coding standards and best practices.
+***
+
 ## Documentation
-Documentation can be found at https://avm99963.github.io/hores-external/. Both the
-UI and the documentation are written in Spanish.
+Documentation can be found at https://avm99963.github.io/hores-external/. Both
+the UI and the documentation are written in Spanish.
 
 ## Contributions
 Contributions in the form of issues or code changes are welcome. You can report