Before there was Rails, there existed other Web Frameworks for Ruby. One of the promising ones is Nitro however it fell into realm of ignorance. On some random surfing I ran across this blog post from one of the main authors of the Nitro Web Framework.
It’s an interesting read since the author laments how Nitro could have been a contender but it never took off. The comments are enlightening since it seems there were project (mis)management issues that prevented a community from really forming around Nitro. Anyways, by now, Rails has the lion’s share of the attention so any hopes now would rest on it being so much better that people will switch. My understanding is that it has some things that are better but not such a big enough jump to make people interested, unfortunately.