Add docs for github credentials.

Author: Dennis Schwartz

README.md

@@ -29,6 +29,10 @@ $ pip install -r requirements.txt
 # migrate the database
 $ python manage.py migrate
 
+# Create a personal Github access token in settings and use github username for CLIENT_ID
+# export Github credentials to bypass rate limit
+$ export GITHUB_CLIENT_ID=<username> && export GITHUB_CLIENT_SECRET=<token>
+
 # start the server
 $ python manage.py runserver