diff --git a/railties/lib/rails/generators/app_base.rb b/railties/lib/rails/generators/app_base.rb
index 5a4691dc0ff664d3fd6c7c8b8ed3e7aea576e727..1a270a6c8ca57f2d81e6dd8108997121756b20d6 100644
--- a/railties/lib/rails/generators/app_base.rb
+++ b/railties/lib/rails/generators/app_base.rb
@@ -297,7 +297,7 @@ def javascript_gemfile_entry
       def javascript_runtime_gemfile_entry
         comment = 'See https://github.com/sstephenson/execjs#readme for more supported runtimes'
         if defined?(JRUBY_VERSION)
-          GemfileEntry.version 'therubyrhino', nil,comment
+          GemfileEntry.version 'therubyrhino', nil, comment
         else
           GemfileEntry.new 'therubyracer', nil, comment, { platforms: :ruby }, true
         end