docs: footer notes (#69)

README.md

@@ -29,7 +29,11 @@ Example usage (you can change the replies for `issue-message` and `pr-message`)
           pr-message: '<h1>It''s great having you contribute to this project</h1> Feel free to create a <strong>Pull Request</strong>! Welcome to the community :nerd_face:'
 ```
 
-### Store community acitivity
+#### Options
+
+`footer` is an optional parameter, which can be used to append the `issue-message` and `pr-message`
+
+### Store community activity
 
 This GitHub Action will log statistics of user activity to Firestore DB (Firebase)