title: unicorn master failed to start
body: <p>i try to start a app via nginx &amp; unicorn .
  i start server successfully for 3 time bye similar codes.
  but i usually see this :</p>
  
  <pre><code>[root@server yaqoot]# unicorn_rails -c config/unicorn.rb -D
  /usr/local/rvm/gems/ruby-2.1.0/gems/unicorn-5.1.0/lib/unicorn/configurator.rb:88:in `block in reload': directory for stderr_path=/var/www/yaqoot/log/unicorn/log not writable (ArgumentError)
      from /usr/local/rvm/gems/ruby-2.1.0/gems/unicorn-5.1.0/lib/unicorn/configurator.rb:84:in `each'
      from /usr/local/rvm/gems/ruby-2.1.0/gems/unicorn-5.1.0/lib/unicorn/configurator.rb:84:in `reload'
      from /usr/local/rvm/gems/ruby-2.1.0/gems/unicorn-5.1.0/lib/unicorn/configurator.rb:65:in `initialize'
      from /usr/local/rvm/gems/ruby-2.1.0/gems/unicorn-5.1.0/lib/unicorn/http_server.rb:76:in `new'
      from /usr/local/rvm/gems/ruby-2.1.0/gems/unicorn-5.1.0/lib/unicorn/http_server.rb:76:in `initialize'
      from /usr/local/rvm/gems/ruby-2.1.0/gems/unicorn-5.1.0/bin/unicorn_rails:209:in `new'
      from /usr/local/rvm/gems/ruby-2.1.0/gems/unicorn-5.1.0/bin/unicorn_rails:209:in `&lt;top (required)&gt;'
      from /usr/local/rvm/gems/ruby-2.1.0/bin/unicorn_rails:23:in `load'
      from /usr/local/rvm/gems/ruby-2.1.0/bin/unicorn_rails:23:in `&lt;main&gt;'
      from /usr/local/rvm/gems/ruby-2.1.0/bin/ruby_executable_hooks:15:in `eval'
      from /usr/local/rvm/gems/ruby-2.1.0/bin/ruby_executable_hooks:15:in `&lt;main&gt;'
  master failed to start, check stderr log for details
  </code></pre>
  
  <p>how i can fix this?</p>