title: Why port 3000 is defaultly selecting in ruby-on-rails
body: <p>If I specify port number separately the specified port number working.</p>
  
  <p><strong>rails s -p 3005</strong>
  now its working with localhost:3005   </p>
  
  <p>But when i use - <strong>rails s</strong> - it running as localhost:3000.</p>
  
  <p>why ruby-on-rails choosing default port is <strong>3000</strong>. </p>