Impossible de trouver le fichier 'jquery' avec le type 'application / javascript'

Cela peut sembler une répétition de la question mais aucune solution ne semble fonctionner pour moi. J'ai gem jquery-rails dans mon Gemfile. Aussi, les lignes

//= require jquery
//= require jquery_ujs
//= require turbolinks
//= require_tree .

Et c'est mon Gemfile:

source 'https://rubygems.org'


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.1'

# Use SCSS for stylesheets
#gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
#gem 'coffee-rails', '~> 4.1.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
#gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc

# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Unicorn as the app server
# gem 'unicorn'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug'
  # Use mysql as the database for Active Record
  gem 'mysql2'
  # Access an IRB console on exception pages or by using <%= console %> in views
  gem 'web-console', '~> 2.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

Ma demande.html.erb :

<!DOCTYPE html>
<html>
<head>
  <title></title>
  <%= stylesheet_link_tag 'application', media: 'all' %>
  <%= javascript_include_tag 'application' %>
  <%= csrf_meta_tags %>
</head>
<body>

<%= yield %>

</body>
</html>

Je ne peux pas lancer mon application Rails. Je ne comprends pas quel est le problème. Ma version de ruby est 2.1.6
S'il vous plaît aider.

source d'informationauteur Souvik Das