Convert Local HTML Web Application to Real-Time Multi-User Collaborative Platform

I have developed a web application in HTML that currently works locally on a single computer. I need to transform this application into a live, online platform where multiple users can access it simultaneously from different computers and collaborate in real-time… (Budget: $30 – $250 USD, Jobs: CSS, Database Management, HTML, JavaScript, MySQL, Node.js, PHP, Python, Web Development, Website Design)