write tutorial about cudf

[haesleinhuepf]

A suggestion by @jni.
The google colab installation is tricky and on Windows it doesn't install. Thus, we might want to elaborate a bit one this.

Hints:

# intall miniconda
!wget -c https://repo.continuum.io/miniconda/Miniconda3-4.5.4-Linux-x86_64.sh
!chmod +x Miniconda3-4.5.4-Linux-x86_64.sh
!bash ./Miniconda3-4.5.4-Linux-x86_64.sh -b -f -p /usr/local

# install RAPIDS packages
!conda install -q -y --prefix /usr/local -c conda-forge \
  -c rapidsai-nightly/label/cuda10.0 -c nvidia/label/cuda10.0 \
  cudf cuml

# set environment vars
import sys, os, shutil
sys.path.append('/usr/local/lib/python3.6/site-packages/')
os.environ['NUMBAPRO_NVVM'] = '/usr/local/cuda/nvvm/lib64/libnvvm.so'
os.environ['NUMBAPRO_LIBDEVICE'] = '/usr/local/cuda/nvvm/libdevice/'

# copy .so files to current working dir
for fn in ['libcudf.so', 'librmm.so']:
  shutil.copy('/usr/local/lib/'+fn, os.getcwd())

Source: https://colab.research.google.com/github/ritchieng/deep-learning-wizard/blob/master/docs/machine_learning/gpu/rapids_cudf.ipynb#scrollTo=qZyMvAQp6iwB