Update README.md

Author: robdodson

README.md

@@ -4,6 +4,10 @@ Hi there! This is the course repo for Udacity Web Accessibility. Contained in
 this repo are a number of sample exercises to help you improve your
 accessibility skills.
 
+## Important note 🚨
+
+The exercises in this repo are for you to complete on your own time. You do not need to send pull requests to this repo when you complete an exercise. Instead, take a look at the next video in the Udacity course where the solution will be shown and compare that to your answer. Sorry for any confusion! 😇
+
 ## Running the examples
 
 Most of the examples can just have their `index.html` dragged into the browser