title: Specified 'redis' for Action Cable pubsub adapter, but the gem is not loaded
body: <p>I am trying to push my application to production which is using action cable. every time i push it gives me an error saying:</p>
  
  <pre><code>ERROR -- Specified 'redis' for Action Cable pubsub adapter, but the gem is not loaded. Add `gem 'redis'` to your Gemfile (and ensure its version is at the minimum required by Action Cable).: nil
  </code></pre>
  
  <p>My Gem file is like:</p>
  
  <pre><code>group :development do
   # Access an IRB console on exception pages or by using &lt;%= console %&gt; in views
   gem 'web-console', '~&gt; 3.0'
   gem 'listen', '~&gt; 3.0.5'
   gem 'spring'
   gem 'spring-watcher-listen', '~&gt; 2.0.0'
   gem 'em-hiredis'
   gem 'redis', '~&gt; 3.0'
  end
  </code></pre>
  
  <p>and My Cable.yml is like:</p>
  
  <pre><code>production:
    adapter: redis
    url: redis://localhost:6379/1
  
  development:
    adapter: async
  
  test:
    adapter: async
  </code></pre>
  
  <p>How should i fix it and make my action cable work on develop.</p>
  
  <p>Gemlock whole:
  This is gem file and redis is specified as <code>redis (~&gt; 3.0)</code></p>
  
  <pre><code>GEM
      remote: https://rubygems.org/
      specs:
        actioncable (5.0.6)
          actionpack (= 5.0.6)
          nio4r (&gt;= 1.2, &lt; 3.0)
          websocket-driver (~&gt; 0.6.1)
        actionmailer (5.0.6)
          actionpack (= 5.0.6)
          actionview (= 5.0.6)
          activejob (= 5.0.6)
          mail (~&gt; 2.5, &gt;= 2.5.4)
          rails-dom-testing (~&gt; 2.0)
        actionpack (5.0.6)
          actionview (= 5.0.6)
          activesupport (= 5.0.6)
          rack (~&gt; 2.0)
          rack-test (~&gt; 0.6.3)
          rails-dom-testing (~&gt; 2.0)
          rails-html-sanitizer (~&gt; 1.0, &gt;= 1.0.2)
        actionview (5.0.6)
          activesupport (= 5.0.6)
          builder (~&gt; 3.1)
          erubis (~&gt; 2.7.0)
          rails-dom-testing (~&gt; 2.0)
          rails-html-sanitizer (~&gt; 1.0, &gt;= 1.0.3)
        activejob (5.0.6)
          activesupport (= 5.0.6)
          globalid (&gt;= 0.3.6)
        activemodel (5.0.6)
          activesupport (= 5.0.6)
        activerecord (5.0.6)
          activemodel (= 5.0.6)
          activesupport (= 5.0.6)
          arel (~&gt; 7.0)
        activesupport (5.0.6)
          concurrent-ruby (~&gt; 1.0, &gt;= 1.0.2)
          i18n (~&gt; 0.7)
          minitest (~&gt; 5.1)
          tzinfo (~&gt; 1.1)
        arel (7.1.4)
        bcrypt (3.1.11)
        bindex (0.5.0)
        builder (3.2.3)
        byebug (9.1.0)
        coderay (1.1.2)
        coffee-rails (4.1.1)
          coffee-script (&gt;= 2.2.0)
          railties (&gt;= 4.0.0, &lt; 5.1.x)
        coffee-script (2.4.1)
          coffee-script-source
          execjs
        coffee-script-source (1.12.2)
        concurrent-ruby (1.0.5)
        crass (1.0.2)
        devise (4.3.0)
          bcrypt (~&gt; 3.0)
          orm_adapter (~&gt; 0.1)
          railties (&gt;= 4.1.0, &lt; 5.2)
          responders
          warden (~&gt; 1.2.3)
        em-hiredis (0.3.1)
          eventmachine (~&gt; 1.0)
          hiredis (~&gt; 0.6.0)
        erubis (2.7.0)
        eventmachine (1.2.5)
        execjs (2.7.0)
        ffi (1.9.18)
        globalid (0.4.1)
          activesupport (&gt;= 4.2.0)
        hiredis (0.6.1)
        i18n (0.9.1)
          concurrent-ruby (~&gt; 1.0)
        jbuilder (2.7.0)
          activesupport (&gt;= 4.2.0)
          multi_json (&gt;= 1.2)
        jquery-rails (4.3.1)
          rails-dom-testing (&gt;= 1, &lt; 3)
          railties (&gt;= 4.2.0)
          thor (&gt;= 0.14, &lt; 2.0)
        listen (3.0.8)
          rb-fsevent (~&gt; 0.9, &gt;= 0.9.4)
          rb-inotify (~&gt; 0.9, &gt;= 0.9.7)
        loofah (2.1.1)
          crass (~&gt; 1.0.2)
          nokogiri (&gt;= 1.5.9)
        mail (2.7.0)
          mini_mime (&gt;= 0.1.1)
        method_source (0.9.0)
        mini_mime (0.1.4)
        mini_portile2 (2.3.0)
        minitest (5.10.3)
        multi_json (1.12.2)
        nio4r (2.1.0)
        nokogiri (1.8.1)
          mini_portile2 (~&gt; 2.3.0)
        orm_adapter (0.5.0)
        pg (0.21.0)
        pry (0.11.2)
          coderay (~&gt; 1.1.0)
          method_source (~&gt; 0.9.0)
        pry-byebug (3.5.0)
          byebug (~&gt; 9.1)
          pry (~&gt; 0.10)
        puma (3.10.0)
        rack (2.0.3)
        rack-test (0.6.3)
          rack (&gt;= 1.0)
        rails (5.0.6)
          actioncable (= 5.0.6)
          actionmailer (= 5.0.6)
          actionpack (= 5.0.6)
          actionview (= 5.0.6)
          activejob (= 5.0.6)
          activemodel (= 5.0.6)
          activerecord (= 5.0.6)
          activesupport (= 5.0.6)
          bundler (&gt;= 1.3.0)
          railties (= 5.0.6)
          sprockets-rails (&gt;= 2.0.0)
        rails-dom-testing (2.0.3)
          activesupport (&gt;= 4.2.0)
          nokogiri (&gt;= 1.6)
        rails-html-sanitizer (1.0.3)
          loofah (~&gt; 2.0)
        railties (5.0.6)
          actionpack (= 5.0.6)
          activesupport (= 5.0.6)
          method_source
          rake (&gt;= 0.8.7)
          thor (&gt;= 0.18.1, &lt; 2.0)
        rake (12.2.1)
        rb-fsevent (0.10.2)
        rb-inotify (0.9.10)
          ffi (&gt;= 0.5.0, &lt; 2)
        redis (3.3.5)
        responders (2.4.0)
          actionpack (&gt;= 4.2.0, &lt; 5.3)
          railties (&gt;= 4.2.0, &lt; 5.3)
        sass (3.5.3)
          sass-listen (~&gt; 4.0.0)
        sass-listen (4.0.0)
          rb-fsevent (~&gt; 0.9, &gt;= 0.9.4)
          rb-inotify (~&gt; 0.9, &gt;= 0.9.7)
        sass-rails (5.0.6)
          railties (&gt;= 4.0.0, &lt; 6)
          sass (~&gt; 3.1)
          sprockets (&gt;= 2.8, &lt; 4.0)
          sprockets-rails (&gt;= 2.0, &lt; 4.0)
          tilt (&gt;= 1.1, &lt; 3)
        semantic-ui-sass (2.2.12.0)
          sass (&gt;= 3.2)
        slim (3.0.8)
          temple (&gt;= 0.7.6, &lt; 0.9)
          tilt (&gt;= 1.3.3, &lt; 2.1)
        slim-rails (3.1.3)
          actionpack (&gt;= 3.1)
          railties (&gt;= 3.1)
          slim (~&gt; 3.0)
        spring (2.0.2)
          activesupport (&gt;= 4.2)
        spring-watcher-listen (2.0.1)
          listen (&gt;= 2.7, &lt; 4.0)
          spring (&gt;= 1.2, &lt; 3.0)
        sprockets (3.7.1)
          concurrent-ruby (~&gt; 1.0)
          rack (&gt; 1, &lt; 3)
        sprockets-rails (3.2.1)
          actionpack (&gt;= 4.0)
          activesupport (&gt;= 4.0)
          sprockets (&gt;= 3.0.0)
        temple (0.8.0)
        thor (0.20.0)
        thread_safe (0.3.6)
        tilt (2.0.8)
        turbolinks (5.0.1)
          turbolinks-source (~&gt; 5)
        turbolinks-source (5.0.3)
        tzinfo (1.2.4)
          thread_safe (~&gt; 0.1)
        uglifier (3.2.0)
          execjs (&gt;= 0.3.0, &lt; 3)
        warden (1.2.7)
          rack (&gt;= 1.0)
        web-console (3.5.1)
          actionview (&gt;= 5.0)
          activemodel (&gt;= 5.0)
          bindex (&gt;= 0.4.0)
          railties (&gt;= 5.0)
        websocket-driver (0.6.5)
          websocket-extensions (&gt;= 0.1.0)
        websocket-extensions (0.1.2)
  
    PLATFORMS
      ruby
  
    DEPENDENCIES
      byebug
      coffee-rails (~&gt; 4.1.0)
      devise
      em-hiredis
      jbuilder (~&gt; 2.0)
      jquery-rails
      listen (~&gt; 3.0.5)
      pg
      pry-byebug
      puma
      rails (&gt;= 5.0.0.beta3, &lt; 5.1)
      redis (~&gt; 3.0)
      sass-rails (~&gt; 5.0)
      semantic-ui-sass
      slim-rails
      spring
      spring-watcher-listen (~&gt; 2.0.0)
      turbolinks (~&gt; 5.x)
      tzinfo-data
      uglifier (&gt;= 1.3.0)
      web-console (~&gt; 3.0)
  
    BUNDLED WITH
       1.16.0
  </code></pre>