Add docker support

Add a dockerfile to the repository, using gunicorn as the flask server initializer.
Add to the README.md file instructions how to setup and have the engine running with minimal effort

This might not be SO easy task without previous knowledge, but a good practice for new comers of how to create a docker that supports machine learning on python.
There are already good base dockerfiles that include Numpy/pandas and such (i.e. anaconda miniconda based docker base)