Admin can login to access private pages (such as add courses)

login.php

@@ -0,0 +1,67 @@
+<?php
+include ("header.html");
+
+session_start();
+
+require_once("User.class.php");
+
+if (empty($_SESSION["connected"]))
+{
+  if (!empty($_POST["username"]) && !empty($_POST["password"]))
+  {
+    $us = User::getUsers();
+
+    foreach($us as $u)
+    {
+      if (strtolower($u->getUsername()) == strtolower($_POST["username"]) && $u->canConnect($_POST["password"]))
+      {
+        $_SESSION["connected"] = true;
+        $_SESSION["who"] = $u->getUsername();
+        die("Vous êtes maintenant connectés !");
+      }
+    }
+    die("Nom d'utilisateur ou mot de passe incorrect.");
+  }
+  else
+  {
+?>
+    <section id="introduction">
+      <article id="login">
+        <h2>Se connecter</h2>
+        <form method="post" action="login.php">
+          <label for="username">Nom d'utilisateur :</label> <input type="text" name="username" id="username" maxlength="32"><br><br>
+
+          <label for="password">Mot de passe :</label> <input type="password" name="password" id="password" maxlength="64"><br><br>
+
+          <input type="submit" name="send" value="Se connecter">
+        </form>
+      </article>
+    </section>
+<?php
+  }
+}
+else
+{
+  if (!empty($_POST["deco"]))
+  {
+    session_destroy();
+    echo "<h2>Vous êtes maintenant déconnecté. À bientôt !</h2>";
+  }
+  else
+  {
+?>
+    <section id="introduction">
+      <article id="login">
+        <h2>Bienvenue <?php echo $_SESSION["who"]; ?></h2>
+        <form method="post" action="login.php">
+          <input type="submit" name="deco" value="Se déconnecter">
+        </form>
+      </article>
+    </section>
+<?php
+  }
+}
+include ("footer.html");
+?>
+  </body>
+</html>