How to deploy flask app to heroku

deployToHeroku

Specify dependencies with Pip

Heroku recognizes Python applications by the existence of a requirements.txt file in the root of a repository. This simple format is used by most Python projects to specify the external Python modules the application requires.
Pip has a nice command (pip freeze) that will generate this file for us:
$ pip freeze > requirements.txt
requirements.txt
Django==1.7
dj-database-url==0.3.0
dj-static==0.0.6
gunicorn==19.1.1
psycopg2==2.5.1
static==0.4
wsgiref==0.1.2
Pip can also be used for advanced dependency management. See Python Dependencies via Pip to learn more.

https://devcenter.heroku.com/articles/getting-started-with-django