i would like to create a pvp javascript game using Rails + some realtime library. It would be a rpg-like game.
I'm already making websites using rails, but i still consider myself as a noob :p
For know, i have found this really good post http://liamkaufman.com/blog/2012/02/25/adding_real-time_to_rails_with_socket.IO_nodejs_and_backbonejs_with_demo/ but i'd like to find one featuring 2 moving objects on a grid (aka my players). For now, let's just assume that there would only be 2 connected players.
I also saw those 2 greats videos from google I/O , but i dont quite understand them: http://www.youtube.com/watch?v=Prkyd5n0P7k and http://www.youtube.com/watch?v=5lMcNPDR6uw
Is there a step by step tutorial somewhere that shows up how to make a pvp game with such technology choice ?
Your question is kind of vague. Are you simply looking for guidance on how to make a game in general using Rails?
The two youtube videos are pretty useful and I was actually about to suggest them to you. You said you didn't really understand them, but rather than having us explain to you what they mean step-by-step, you should be able to learn everything from what they've done.
At the end of the video, they tell you how to get involved. GRITS is open-source and you can actually look at ALL their code and slowly learn here. If there are some technologies you are unfamiliar with, just look them up. There are great tutorials everywhere.
Stackoverflow is a lot more useful for solving specific questions i.e. Hey I am trying to develop something, here is what I have tried/done but it isn't doing what I want. What can I do to fix it? If you ever have trouble, don't be afraid to come here and ask. There are a LOT of things that go into making a game (I mean the Google I/O videos are spanned over 2 hours and they basically did a rush job in explaining the gist of the game) and there are many ways to go about it. Hope this helps.