Doc: Update the ToC

Author: GitauHarrison

README.md

@@ -18,7 +18,6 @@ This repository holds all the notes of the things I have learnt. You can use it
 9. [Integrate Google reCaptcha in Flask](recaptcha.md)
 10. [Adding markdown editing to Flask-WTF forms](handling_rich_text.md)
 11. [Setting Up Ngrok](localhost_testing.md)
-12. [Install Elasticsearch](elasticsearch_installation.md)
 13. [Add File Uploads to Database](upload_files_to_database.md)
 14. [Build a simple WhatsApp chatbot using Flask and Twilio](whatsapp_chatbots/simple_whatsapp_chatbot.md)
 15. [Build a video call application using Flask and Twilio](video_call_app/simple_video_call_app.md)