404 not found error after converting project from jade to pug node js

I had a project which requires logging in as admin and then the page redirects to the admin panel. Now, my project was working fine in Jade template but after upgrading to pug and renaming all views I am getting this problem:

Error: Not Found at /Users/uzayrhussain/Desktop/OOES2/app.js:53:13

This is login.pug

doctype html
html(lang='en')
  head


  body
    // Top content
    .top-content
      .inner-bg
        .container
          .row
            .col-sm-8.col-sm-offset-2.text
              h1
                strong Login
          .row
            .col-sm-3
              a.btn.btn-info(href='/', role='button') Go Back!
            .col-sm-6.form-box
              .form-top
                .form-top-left
                  h3 Fill the form to sign in:
              .form-bottom
                form.login-form(role='formlogin', action='login/#{method}', method='post')
                  .form-group
                    label.sr-only(for='form-username') Username
                    input#form-username.form-username.form-control(type='text', name='username', placeholder="username")
                  .form-group
                    label.sr-only(for='form-password') Password
                    input#form-password.form-password.form-control(type='password', name='password', placeholder="password")
                  button.btn(type='submit') Login
            .col-sm-3

    // Javascript

    //if lt IE 10

App.js

var app = express();

require('./config/passport')(passport);

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
app.use(logger('dev'));
app.use(cookieParser());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, 'public')));

app.use(session({secret: 'my_app_secret'}));
app.use(passport.initialize());
app.use(passport.session());
app.use(flash());



var monk = require('monk');
var db = monk('localhost:27017/examdb');

var admin = require('./controllers/admin');
var login = require('./controllers/login_controller');
var index = require('./controllers/index');

app.use('/',index);
app.use('/login', login);
app.use('/admin', admin);

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
//app.use(cookieParser());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, 'public')));


// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});


// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}


// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});


module.exports = app;