My question is why foreman start not serving css file in dev environment ...? but my app running perfectly fine in heroku production server. Correct me if i am wrong, i thou
Try setting dj-static==0.0.6
in your requirements.txt file for Virtualenv. There might be a versioning issue on PyPI or a Django1.7 issue or the Heroku tutorial shows to use 0.0.5.
I've reported this issue to Heroku and their tutorial is now updated to reflect newer versions in the requirements.txt.