title: Rails server not starting due to `require': cannot load such file -- bcrypt_ext (LoadError)
body: <p>I am new to rails and using current rails 5 version with ruby 2.3.0 and i have install device gem for autentication but server is not getting started <a href="http://guides.railsgirls.com/devise" rel="nofollow noreferrer">Rails guide for devise</a></p>
  
  <p>I have follow all the step and also added gem 'bcrypt', '~> 3.1.7'
   in my gemfile. since i am using windows 10 the server is not getting started </p>
  
  <pre><code>C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/dependencies.rb:293:in `require': cannot load such file -- bcrypt_ext (LoadError)
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/dependencies.rb:293:in `block in require'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/dependencies.rb:259:in `load_dependency'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/dependencies.rb:293:in `require'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bcrypt-3.1.11-x86-mingw32/lib/bcrypt.rb:16:in `rescue in &lt;top (required)&gt;'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bcrypt-3.1.11-x86-mingw32/lib/bcrypt.rb:12:in `&lt;top (required)&gt;'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bundler-1.14.3/lib/bundler/runtime.rb:91:in `require'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bundler-1.14.3/lib/bundler/runtime.rb:91:in `block (2 levels) in require'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bundler-1.14.3/lib/bundler/runtime.rb:86:in `each'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bundler-1.14.3/lib/bundler/runtime.rb:86:in `block in require'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bundler-1.14.3/lib/bundler/runtime.rb:75:in `each'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bundler-1.14.3/lib/bundler/runtime.rb:75:in `require'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/bundler-1.14.3/lib/bundler.rb:107:in `require'
          from C:/Sites/testproject/config/application.rb:7:in `&lt;top (required)&gt;'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/commands/commands_tasks.rb:88:in `require'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/commands/commands_tasks.rb:88:in `block in server'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/commands/commands_tasks.rb:85:in `tap'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/commands/commands_tasks.rb:85:in `server'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
          from C:/RailsInstaller/Ruby2.3.0/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/commands.rb:18:in `&lt;top (required)&gt;'
          from bin/rails:4:in `require'
          from bin/rails:4:in `&lt;main&gt;'
  </code></pre>
  
  <p>my gem file is below :</p>
  
  <pre><code>source 'https://rubygems.org'
  
  git_source(:github) do |repo_name|
    repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
    "https://github.com/#{repo_name}.git"
  end
  
  
  # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
  gem 'rails', '~&gt; 5.0.1'
  # Use sqlite3 as the database for Active Record
  #gem 'sqlite3'
  gem 'pg'
  gem 'devise'
  
  # Use Puma as the app server
  gem 'puma', '~&gt; 3.0'
  # Use SCSS for stylesheets
  gem 'sass-rails', '~&gt; 5.0'
  # Use Uglifier as compressor for JavaScript assets
  gem 'uglifier', '&gt;= 1.3.0'
  # Use CoffeeScript for .coffee assets and views
  gem 'coffee-rails', '~&gt; 4.2'
  # 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 navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
  gem 'turbolinks', '~&gt; 5'
  # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
  gem 'jbuilder', '~&gt; 2.5'
  # Use Redis adapter to run Action Cable in production
  # gem 'redis', '~&gt; 3.0'
  # Use ActiveModel has_secure_password
  gem 'bcrypt', '~&gt; 3.1.11'
  
  # 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', platform: :mri
  end
  
  group :development do
    # Access an IRB console on exception pages or by using &lt;%= console %&gt; anywhere in the code.
    gem 'web-console', '&gt;= 3.3.0'
  end
  
  # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
  gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
  </code></pre>