[luckystartup]

It's not hard to scale a Rails server, when compared to other frameworks and languages. It's exactly the same as scaling a server written in Java, Node.js, Python, or any other language. You just spin up more machines and put them behind a load balancer.

Yes, Ruby is slower than other programming languages, but this usually doesn't matter. If you are charging people to use your software, or even if you are serving ads, you will always be making money before you need a second server. Plus, Rails is super productive, so you'll be able to build your product much faster.

I'm not sure why GitHub used a patched Ruby version, but no, that's not necessary.

Having said all of that, I'm moving towards Elixir and Phoenix. Not just because of the performance, but also because I really like the language and framework.