title: Bootstrap-Sprockets Error: File to import not found or unreadable: bootstrap-sprockets
body: <p>I'm attempting to implement bootstrap into my app and I keep getting a couple errors that I've never received when starting apps before. I browsed for an answer and the only answers I keep finding are to remove the <code>assets</code> part of the Gemfile which I don't have and to restart the server which I've done several times with no luck. Below are the errors and my files. Please let me know if something else needs to be provided. Thank you!</p>
  
  <p><strong>Browser Error:</strong> 
  <code>File to import not found or unreadable: bootstrap-sprockets</code></p>
  
  <p><strong>Rails Server Warnings:</strong></p>
  
  <pre><code>/Users/tucker/.rvm/gems/ruby-2.2.1/gems/bootstrap-sass-3.3.6/lib/bootstrap-sass/version.rb:2: warning: already initialized constant Bootstrap::VERSION
  /Users/tucker/.rvm/gems/ruby-2.2.1/gems/bootstrap-4.0.0.alpha3/lib/bootstrap/version.rb:2: warning: previous definition of VERSION was here
  /Users/tucker/.rvm/gems/ruby-2.2.1/gems/bootstrap-sass-3.3.6/lib/bootstrap-sass/version.rb:3: warning: already initialized constant Bootstrap::BOOTSTRAP_SHA
  /Users/tucker/.rvm/gems/ruby-2.2.1/gems/bootstrap-4.0.0.alpha3/lib/bootstrap/version.rb:3: warning: previous definition of BOOTSTRAP_SHA was here
  </code></pre>
  
  <p><strong>Gemfile:</strong></p>
  
  <pre><code>source 'https://rubygems.org'
  
  gem 'rails', '4.2.5'
  
  group :production do
    gem 'pg'
    gem 'rails_12factor'
  end
  
  group :development do
    gem 'sqlite3'
  end
  
  gem 'sass-rails', '~&gt; 5.0'
  gem 'uglifier', '&gt;= 1.3.0'
  gem 'coffee-rails', '~&gt; 4.1.0'
  gem 'jquery-rails'
  gem 'turbolinks'
  gem 'bootstrap'
  gem 'figaro'
  gem 'pry'
  gem 'jbuilder', '~&gt; 2.0'
  gem 'sdoc', '~&gt; 0.4.0', group: :doc
  gem 'bootstrap-sass'
  
  group :development, :test do
    gem 'byebug'
    gem 'web-console', '~&gt; 2.0'
    gem 'spring'
    gem 'rspec-rails'
    gem 'shoulda'
    gem 'faker'
    gem 'factory_girl_rails'
  end
  </code></pre>
  
  <p><strong>Application.js:</strong></p>
  
  <pre><code>//= require jquery
  //= require bootstrap-sprockets
  //= require jquery_ujs
  //= require turbolinks
  //= require_tree .
  </code></pre>
  
  <p><strong>Application.scss:</strong></p>
  
  <pre><code>...
  
  *= require_tree .
   *= require_self
   */
  
  @import "bootstrap-sprockets";
  @import "bootstrap";
  </code></pre>