Added README

Author: benfogle

README.rst

@@ -0,0 +1,46 @@
+Python Cross Compiling Example
+==============================
+
+This repository is a worked example of cross compiling a non-trivial Python app
+to run on Android. It is the companion to the Python Cross-Compiling Guide (as
+yet unpublished). The makefile above will download all dependencies, build
+them, and produce a tarball containing:
+
+- Python 3.6 for Android (ARM)
+- numpy
+- Pandas
+- matplotlib
+- Pillow
+- Example Python scripts
+
+
+Building
+========
+
+The makefile is written and tested on Ubuntu 16.04. Consult
+``docker/Dockerfile`` in this repository for details of the prerequisites that
+should be installed on the build machine.
+
+To build, it should be enough to run ``make``.
+
+To build using Docker:
+
+.. code:: sh
+
+    $ docker run --rm \
+        -v /path/to/working:/working \
+        -v /path/to/output:/output \
+        -v /path/to/this/repo:/source \
+        benfogle/python-cross-compiling-example
+
+Where ``working`` is a scratch directory for intermediate build files.
+
+
+Running
+=======
+
+To run, use adb to push the resulting files to the Android device. Rather than
+run Python directly, which requires setting ``LD_LIBRARY_PATH``, run the script
+``bin/apython``, which will set it for you. Examples are in the
+``examples`` directory.
+