Adding 2 lines in Readme

[shloka-gupta]

Is your feature request related to a problem? Please describe. While running the programming, I got ModuleNotFoundError: No module named 'django_heroku' despite installing requirements. Other users should not face the same issue

Describe the solution you'd like The one that I'm adding

Describe alternatives you've considered None

Additional context

[shloka-gupta]

My Bad. I didn't see it in the requirements file