Updated README to show json file screenshot instead of config.py screenshot

README.md

@@ -36,7 +36,7 @@ To interface with Canvas, you need a Canvas API Key.
   browser's popup window and paste it between the opening- and closing-quotes 
   in `~/.abet_oat.json`.
 
-  ![Copy/Paste your Canvas API Key into config.py](README-images/config-py.png)
+  ![Copy/Paste your Canvas API Key into config.py](README-images/abet_oat-json.png)
 
 ### You no longer need to...