update README not that there's tests

README.md

diff --git a/README.md b/README.md
index b524b15..607bc6e 100644
--- a/README.md
+++ b/README.md
@@ -42,3 +42,9 @@
     ],
 )
 ```
+
+## Development
+
+### Testing
+
+`bazel test //...`