couldn't find file 'jquery' in Rails project

Question

I'm working through the Agile Web Development book with Rails version 3.2.13 and Ruby 2.0.0, but I keep getting the following error when trying to access localhost:3000:

Sprockets::FileNotFound in Store#index

couldn't find file 'jquery' (in /Users/.../app/assets/javascripts/application.js:13)

My application.js file:

// This is a manifest file that'll be compiled into application.js, which will include all the files
// listed below.
//
// ...
//    
//= require jquery
//= require jquery-ui
//= require jquery_ujs
//= require_tree .

In my Gemfile, I have gem 'jquery-rails', '~> 2.3.0' and have attempted many different solutions I found on the internet to no avail.

Answer 1

I got it to work.

1. Put gem 'jquery-rails', "~> 2.3.0" into Gemfile.
2. Remove Gemfile.lock by typing rm Gemfile.lock into the terminal.
3. Run bundle install from the terminal
4. Make sure //= require jquery-ui is in application.js

Note: If step 3 doesn't work, then run sudo gem install jquery-rails -v 2.3.0 through the terminal.