title: Rails: Address already in use - bind(2) (Errno::EADDRINUSE)
body: <p>I am trying to deploy Rails app with the Puma web server. When trying to start Puma server with a config file <code>bundle exec puma -C config/puma.rb</code> I get an error that the address is already in use.</p>
  
  <p>Does someone know how to fix this?</p>
  
  <pre><code>bundle exec puma -C config/puma.rb
  [23699] Puma starting in cluster mode...
  [23699] * Version 2.11.3 (ruby 2.0.0-p353), codename: Intrepid Squirrel
  [23699] * Min threads: 5, max threads: 5
  [23699] * Environment: development
  [23699] * Process workers: 2
  [23699] * Preloading application
  Jdbc-MySQL is only for use with JRuby
  [23699] * Listening on tcp://0.0.0.0:3000
  /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `initialize': Address already in use - bind(2) (Errno::EADDRINUSE)
      from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `new'
      from /Users/lexi87/.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `add_tcp_listener'
      from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:96:in `block in parse'
      from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:82:in `each'
      from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:82:in `parse'
      from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/runner.rb:119:in `load_and_bind'
      from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/cluster.rb:302:in `run'
      from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/cli.rb:216:in `run'
      from /rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/bin/puma:10:in `&lt;top (required)&gt;'
      from /.rvm/gems/ruby-2.0.0-p353/bin/puma:23:in `load'
      from /.rvm/gems/ruby-2.0.0-p353/bin/puma:23:in `&lt;main&gt;'
      from /.rvm/gems/ruby-2.0.0-p353/bin/ruby_executable_hooks:15:in `eval'
      from /.rvm/gems/ruby-2.0.0-p353/bin/ruby_executable_hooks:15:in `&lt;main&gt;'
  </code></pre>