I have an app that makes use of shortuuid (https://pypi.python.org/pypi/shortuuid/0.1) that is working fine locally when I run it with runapp.py:
import os
Place a requirements.txt in the root directory of your git repo, with your required dependencies (specified in pip/easy-install format).
requirements.txt
Example taken from the Heroku website:
Flask==0.8 Jinja2==2.6 Werkzeug==0.8.3 certifi==0.0.8 chardet==1.0.1 distribute==0.6.24 gunicorn==0.14.2 requests==0.11.1