update documentation

Author: Meesch

backend/README.md

@@ -51,7 +51,7 @@ Create and activate a virtualenv. Ensure your working directory is the one that
 ```console
 $ psql -f create_db.sql
 $ pip install pip-tools
-$ pip sync
+$ pip-sync
 $ python manage.py migrate
 $ python manage.py createsuperuser
 ```

frontend/README.md

@@ -1,5 +1,11 @@
 # LangPro Annotator frontend
 
+## Before you start
+You need to install the following software:
+ - Node ^18.19.1 || ^20.11.1 || >=22.0.0
+
+Run `yarn` to install the requirements for the frontend.
+
 ## Import ProofBank data
 
 LangPro Annotator can be used to browse and annotate problems from the ProofBank dataset, which is a collection of problems from both the [SICK (Sentences Involving Compositional Knowledge)][1] and FraCaS (Framework for Computational Semantics) datasets. For more information about these datasets, see the [References](#references) section below.