Wouldn't it make more sense to test various features of Ruby for comparison rather than comparing an entire web framework? Given that, the URL should be israilsfastyet.com, or more appropriately howdoesrailsbehaveonvariousrubyversions.com
Of course, it's not a real Rails app presumably, but just a sample/dummy one. So you may or may not see comparable speed-up with a real app. But it's probably suggestive of the upper limit of improvement you can get by switching ruby versions.
"Will I get a performance improvement from my Rails app by upgrading ruby" is a real question a lot of people will have. Micro-benchmarks of ruby wouldn't answer it as well as the OP does.