Fix wrong link in readme (#66)

Signed-off-by: ClemensLinnhoff <[email protected]>

Author: ClemensLinnhoff

README.md

@@ -3,7 +3,10 @@
 
 > **_NOTE:_**  This tool is not part of the official OSI standard. It has its own release schedule. The OSI CCB is not responsible for this software but MUST be notified about pull requests.
 
-OSI Validator checks the compliance of OSI messages with predefined [rules](https://github.com/OpenSimulationInterface/osi-validation/tree/master/rules). The full documentation on the validator and customization of the rules is available [here](https://github.com/OpenSimulationInterface/osi-validation/tree/master/doc).
+OSI Validator checks the compliance of OSI messages with predefined rules.
+These rules can be generated from the OSI .proto files with [rules2yml.py](https://github.com/OpenSimulationInterface/osi-validation/blob/master/rules2yml.py).
+After the rules are generated, they can be customized by the user.
+The full documentation on the validator and customization of the rules is available [here](https://github.com/OpenSimulationInterface/osi-validation/tree/master/doc).
 
 ## Usage