Ruby on Rails was created by David Heinemeier Hansson in 2004. The idea arose because he noticed that, as he was making web applications with Ruby, he was copy pasting common parts from previous apps into his new work. As a developer, he (and all of us) loved solving hard problems. The only way to get to solving the hard problems that are unique to the domain you are working in is to go up a layer of abstraction. The nitty-gritty of basic web apps should be removed from your head. That was the idea behind Rails: it handles the repetitive code that is common across apps and enables you to focus on the hard bits.
As always we are going to walk you up layers of abstraction. What that means is it will take a few lessons before you start to really feel the "magic" of Rails. That's good! Sometimes Rails provides so much magic that you don't actually know what's going on. Hopefully by understanding the HTTP underneath and by increasing levels of abstraction this will be mitigated.
Have a ton of fun. Rails changed the way Web Apps are developed; enjoy the spoils of many open source contributors' hard work.