Learn jQuery with Rails
In order to learn jQuery fast, and use it within your Ruby on Rails project, we would advise the following steps:
Learn basics of JavaScript
You can freely skip some steps here and there which you find that you already know.
https://www.codecademy.com/learn/javascript
Learn basics of jQuery
https://www.codecademy.com/learn/jquery
When you finish learning basics of JavaScript so you can move to their usage inside of Rails app.
Basics of unobtrusive JavaScript in Rails
The following tutorial will show you how to trigger JavaScript and usage on some basic actions in Rails.
http://railscasts.com/episodes/205-unobtrusive-javascript
jQuery with Rails
The following video will teach you how to get around everything that you would need in order to master jQuery in Rails.
https://www.youtube.com/watch?v=FBxVN7U1Qsk