Added instructions to set up backend

[NOOB-3301]

Fixes Issue🛠️

Closes #91

Description👨‍💻

I have added setup instructions for the backend.

Type of Change📄

• Documentation (non-breaking change which updates or adds documentation)

Checklist✅

• I am an Open Source contributor
• I have performed a self-review of my code
• My code follows the style guidelines of this project

Screenshots/GIF📷

[github-actions]

Hey @NOOB-3301, Welcome to the project Eventica! 🎊
Thanks for your contribution! Your effort makes this project better. Keep it up! 🙌
Please wait for the PR to be reviewed. Happy Coding!! ✨

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[Rakesh9100]

Please make the instructions more clear for setting up the backend, from the basic to the most advanced stages. Also, we have assets/register folder which has login and register form codes, so how can one integrate this with your backend codes using Netlify or vercel for backend @NOOB-3301

[github-actions]

Congrats, Your pull request has been successfully merged 🥳🎉 Thank you for your contribution to my project 🚀 Keep Contributing!! ✨ @NOOB-3301