Improved README so devs don’t cry trying to set this up

[codex-blip]

This PR adds proper setup instructions to the README because:

• I cloned the repo and immediately got lost 🧭
• There was no manage.py, no settings.py, and lots of confusion 😅
• Now it clearly explains: “Hey, this is a reusable app, not a full project!”

Also updated:

• Installation steps (with pip + setup.py)
• How to plug into your own Django project
• Modern urls.py syntax for Django 3+
• Fixed markdown formatting to help your eyeballs 👀

Now beginners (like me) can actually use this without panic.

Cheers 🍻