CONTRIBUTING.md in json_matchers-0.7.3 vs CONTRIBUTING.md in json_matchers-0.8.0

@@ -1,10 +1,11 @@
-Contributing to json_matchers:
+Contributing to `json_matchers`:
 
 1. Fork the [official repository](https://github.com/thoughtbot/json_matchers/tree/master).
 2. Make your changes in a topic branch.
 3. Send a pull request.
 
 Notes:
 
-* Contributions without tests won't be accepted.
+* Contributions without tests covering the `RSpec` matchers _and_ the `Minitest`
+  assertions won't be accepted.
 * Please don't update the Gem version.