ihuston/ipython-notebook-buildpack — pull request #2 by p-a-c-o (2014-12-17 07:53:17+00:00)
Title: Add support for a runtime.txt to determine miniconda version.

Changing the runtime to miniconda3 also changes the default python version to python 3.x. Not sure if runtime.txt is a good wording, but it is also used in the python buildpack.