index.php

<?php
require 'vendor/autoload.php';
date_default_timezone_set("America/Mexico_City");

//use Monolog\Logger;
//use Monolo\Handler\StreamHandler;
//$log = new Logger('name');
//$log->pushHandler(new StreamHandler('app.txt', Logger::WARNING));
//$log->addWarning('Oh Noes.');

$app = new \Slim\Slim( array(
     'view' => new \Slim\Views\Twig()
));
$app->add(new \Slim\Middleware\SessionCookie());

$view = $app->view();
$view->parserOptions = array(
    'debug' => true
);
$view->parserExtensions = array(
    new \Slim\Views\TwigExtension(),
);

$app->get('/', function() use($app){
  $app->render('about.twig');
})->name('home');

$app->get('/contact', function() use($app) {
  $app->render('contact.twig');
})->name('contact');

$app->post('/contact', function() use($app) {
  $name = $app->request->post('name');
  $email = $app->request->post('email');
  $msg = $app->request->post('msg');
  if (!empty($name) && !empty($email) && !empty($msg)) {
      $cleanName = filter_var($name, FILTER_SANITIZE_STRING);
      $cleanEmail = filter_var($email, FILTER_SANITIZE_EMAIL);
      $cleanMsg = filter_var($msg, FILTER_SANITIZE_STRING);
  }   else {
     $app->flash('fail', 'All Fields Are Required.');
     $app->redirect('/contact');
  }

  $transport = Swift_SendmailTransport::newInstance('/usr/sbin/sendmail -bs');
  $mailer = \Swift_Mailer::newInstance($transport);

  $message = \Swift_Message::newInstance();
  $message->setSubject('Email From Our Website');
  $message->setFrom(array(
          $cleanEmail => $cleanName
 ));
 $message->setTo(array('testaccountthatdoesnotexist@emailprovider.com'));
 $message->setBody($cleanMsg);

 $result = $mailer->send($message);

 if($result > 0 ) {
     // send a message that says thank you.
     $app->flash('success', 'Thanks So Much! You are AWESOME!!!');
     $app->redirect('/');
} else {
     $app->flash('fail', 'Something went wrong, please try again later.');
     // log that there was an error
     $app->redirect('/contact');
}

});

$app->run();