add note about env var

Author: Tyler Hutcherson

README.md

@@ -4,5 +4,8 @@ This template shows basic usage of Metis Machine curated data, 3rd party data, a
 ## Dependencies
 User must aqcuire an API key from [quandl](https://www.quandl.com/) if they wish to use. Otherwise, user can provide their own coin data.
 
+Set the API key using the skafos CLI:
+`skafos env QUANDL_KEY --set <API KEY>`
+
 ## Model Tuning
 The project represents the bare bones of what it takes to build a sophisticated deep learning model. More hyperparameter tuning, feature engineering, and optimizer testing will improve the model's performance.