Add Dockerfile for Easy Deployment (Level-2)

[Aripilli-Bhavana]

Currently, deployment is limited to Render. Adding a Dockerfile will allow users to containerize the app and run it locally or deploy it on any platform (AWS, GCP, Azure, Heroku).
Tasks:

Write a Dockerfile with Python environment setup

Add instructions in README for Docker build & run

Test Dockerized app locally.

If interested add a level 2 label to this and assign it to me so that I can proceed.

[Deepika14145]

Please fix this issue; otherwise, it will be assigned to someone else. @Aripilli-Bhavana