updated readme

test/performance/browsing_test.rb

@@ -0,0 +1,9 @@
+require 'test_helper'
+require 'rails/performance_test_help'
+
+# Profiling results for each test method are written to tmp/performance.
+class BrowsingTest < ActionDispatch::PerformanceTest
+  def test_homepage
+    get '/'
+  end
+end