Add troubleshooting section + fix error regarding rmagick

README.md

@@ -6,3 +6,12 @@ you'll gain insights into your team's strengths, areas for improvement, and
 practical steps to advance your CD maturity. The results can serve as a
 baseline for tracking progress and aligning future improvements with best
 practices in software delivery.
+
+## Troubleshooting
+
+If you get an error regarding the gem `rmagick` when you run `bundle install`
+on Mac OS, you may need to install `imagemagick` first.
+
+```sh
+brew install imagemagick
+```