added req.txt file to help determine the dependencies required to run…

[saksham-2000]

I think the 'req.txt' is important in a project so that beginners who are looking at your project on github and want to use to it are able to install all the dependencies required to run this project.

After cloning, one has to simply go this folder and write this command on the terminal/command prompt: pip install -r req.txt and then after updating the database according to their needs, they can simply run the plag.py file