diff --git a/README.markdown b/README.markdown
index 841c88d5e0..83b9bc189b 100644
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+++ b/README.markdown
@@ -10,6 +10,7 @@ produce.
 * Rails 3.2.x
 * Ruby >= 1.9.3
 * PostgreSQL database
+* PhantomJS (for testing)
 * See Gemfile for a list of gems required