old_contents: 
  /**
   * Module dependencies.
   */
  
  var express = require('express'),
      engine = require('ejs-locals'),
      db = require('./db'),
      home = require('./routes'),
      about = require('./routes/about'),
      todo = require('./routes/todo'),
      threejs = require('./routes/threejs'),
      http = require('http'),
      path = require('path');
  
  var app = express();
  
  // use ejs-locals for all ejs templates
  app.engine('ejs', engine);
  
  // all environments
  app.set('port', process.env.PORT || 3000);
  app.set('views', __dirname + '/views');
  app.set('view engine', 'ejs');
  app.use(express.favicon());
  app.use(express.logger('dev'));
  app.use(express.bodyParser());
  app.use(express.methodOverride());
  app.use(express.cookieParser('secret'));
  app.use(express.session());
  app.use('/todo', todo.current_user);
  app.use(app.router);
  app.use(require('stylus').middleware(__dirname + '/public'));
  app.use(express.static(path.join(__dirname, 'public')));
  
  // development only
  if ('development' == app.get('env')) {
    app.use(express.errorHandler());
  }
  
  app.get('/', home.index);
  app.get('/about', about.index);
  app.get('/threejs', threejs.index);
  
  // Todo list
  app.get('/todo', todo.index);
  app.post('/todo/add', todo.add);
  app.get('/todo/edit/:id', todo.index);
  app.post('/todo/edit/:id', todo.edit);
  app.get('/todo/delete/:id', todo.destroy);
  
  http.createServer(app).listen(app.get('port'), function(){
    console.log('Express server listening on port ' + app.get('port'));
  });
new_contents: 
  /**
   * Module dependencies.
   */
  
  var express = require('express'),
      engine = require('ejs-locals'),
      db = require('./db'),
      home = require('./routes'),
      about = require('./routes/about'),
      todo = require('./routes/todo'),
      threejs = require('./routes/threejs'),
      http = require('http'),
      path = require('path');
  
  var app = express();
  
  // use ejs-locals for all ejs templates
  app.engine('ejs', engine);
  
  // all environments
  app.configure(function(){
      app.set('port', process.env.PORT || 3000);
      app.set('views', __dirname + '/views');
      app.set('view engine', 'ejs');
      app.use(express.favicon());
      app.use(express.logger('dev'));
      app.use(express.bodyParser());
      app.use(express.methodOverride());
      app.use(express.cookieParser('secret'));
      app.use(express.session());
      app.use('/todo', todo.current_user);
      app.use(app.router);
      app.use(require('stylus').middleware(__dirname + '/public'));
      app.use(express.static(path.join(__dirname, 'public')));
  });
  
  // development only
  app.configure('development', function(){
      app.use(express.errorHandler());
  });
  
  // production
  app.configure('production', function(){
      //...
  });
  
  app.get('/', home.index);
  app.get('/about', about.index);
  app.get('/threejs', threejs.index);
  
  // Todo list
  app.get('/todo', todo.index);
  app.post('/todo/add', todo.add);
  app.get('/todo/edit/:id', todo.index);
  app.post('/todo/edit/:id', todo.edit);
  app.get('/todo/delete/:id', todo.destroy);
  
  http.createServer(app).listen(app.get('port'), function(){
    console.log('Express server listening on port ' + app.get('port'));
  });
subject: Change configuration settings