title: How to save pip packages
body: <p>We have a python/django based web application, many components of which are installed using pip. So I would like to ask if there is a way to save or download and save the particular python packages that we are having pip install (example: pip install django==1.5.1). We would like to have in the end a collection of the packages in the versions known to be working and with which the app was developed locally. Any and all advice will be appreciated.</p>