<script src="js/jQuery.validate.min.js"></script>change Q to q

 <link href="cs/bootstrap.css" rel="stylesheet"> miss "s", it doesn't
link to correct file, so it should be:
   <link href="css/bootstrap.css" rel="stylesheet">

 <link href="cs/signin.css" rel="stylesheet"> miss "s", it doesn't link
to correct file, so it should be:
   <link href="css/signin.css" rel="stylesheet">

 file " jQuery.validate.min.js  " should be change to lower case "q",
so it should be
   <script src="js/jquery.validate.min.js"></script>

 doesn't link to jQuery file,add "<script
src="js/jquery.min.js"></script>", so it should be:
     <script src="js/jquery.min.js"></script>
     <script src="js/jquery.validate.min.js"></script>
     <script src="js/application.js"></script>

 $('submit').click(function(event) miss "#" because it's an id, it
should be:
   $('#submit').click(function(event)

 add "$" in front of ('.form').validate, so it should be:
  $('.form').validate

$('.form').validate it is not a class, it is an id, so it should be:
  $('#form').validate

 rules miss" : " , so it should be:
    rules:

 miss " } " in validate function, so it should be:
rules:  {
 			username : {
 				required: true,
 				email : true
 				minlength : jQuery.format("Your password is at least {0}
characters long"),
 				maxlength : jQuery.format("Your password can't be longer than {0}
characters")

		                              }
 		}