Add Rapids performance tests

Author: gjbex

source-code/rapids/README.md

@@ -0,0 +1,12 @@
+# Rapids
+
+NVIDIA Rapids provides a framework to do data science efficiently
+on GPUs.
+
+
+## What is it?
+
+1. `environment.yml`: conda environment description to run the notebooks
+   and scripts in this directory.
+1. `cudf.ipynb`: Jupyter notebook comparing the performance of pandas
+   dataframes to that of Rapids dataframes on some common operations.