Merge pull request #5492 from arunagw/build_fix_app_generator_test

Build fix for app_generator_test.rb

railties/test/generators/app_generator_test.rb

@@ -236,7 +236,7 @@ def test_inclusion_of_javascript_runtime
     if defined?(JRUBY_VERSION)
       assert_file "Gemfile", /gem\s+["']therubyrhino["']$/
     else
-      assert_file "Gemfile", /# gem\s+["']therubyracer["']$/
+      assert_file "Gemfile", /# gem\s+["']therubyracer["']+, :platform => :ruby$/
     end
   end