Add git pre-push examples in README

Author: cwang39403

README.md

@@ -164,7 +164,7 @@ pip3 install -r requirements.txt
 
 The `pre-push` git hook should be installed to avoid **project-specific** validation functions (which should be defined and stored under `esdlvalidator/validation/functions/projects/`) from being pushed to an open GitHub repository. 
 
-This does not affect when pushing changes to the internal gitlab repository (both project-specific functions and generic functions can be pushed to remotes).
+This does not affect when pushing changes to the internal gitlab repository (both project-specific or generic functions can be pushed to remotes).
 
 At the project root, run the command in a bash terminal to set up git hooks.
 
@@ -180,6 +180,24 @@ Setting up Git hooks...
 ```
 
 
+#### Examples
+
+When pushing to the internal gitlab repository with `git push`, you would see message like below and then proceed.
+
+```
+Pre-push hook triggered for remote https://ci.tno.nl/gitlab/warmingup/chess-preprocessor.git
+...
+```
+
+When pushing to the open GitHub repository with `git push`, and if there are any files and changes made under `esdlvalidator/validation/functions/projects/`, the push action is aborted with the following message.
+
+```
+Pre-push hook triggered for remote https://github.com/ESDLMapEditorESSIM/ESDLValidator.git
+Pushing to GitHub. Checking files under esdlvalidator/validation/functions/projects/ ...
+❌ Push to GitHub rejected! The following files are in the blocked 'esdlvalidator/validation/functions/projects/' directory:
+esdlvalidator/validation/functions/projects/nwn/test.py
+➡️ These files must not be pushed to GitHub. Push to GitLab is allowed.
+```
 
 ### Testing