I need to install rdkit in heroku for my heroku app to run. I installed rdkit locally in my laptop by using 

`sudo apt-get install python-rdkit`. 

But when I generated the requirements file using `pip freeze` , the generated file is not showing the rdkit. And `pip install python-rdkit` or `pip install rdkit` are not working. Can any one please tell me how can I install rdkit on heroku?