diff --git a/project/src/index.php b/project/src/index.php
index 81dc0eb..521985c 100644
--- a/project/src/index.php
+++ b/project/src/index.php
@@ -4,6 +4,7 @@
 test
 
 <?php
+use model\Connection;
 
 require_once("Connection.php");
 
diff --git a/project/src/model/gateways/AdminGateway.php b/project/src/model/gateways/AdminGateway.php
new file mode 100644
index 0000000..efcd47c
--- /dev/null
+++ b/project/src/model/gateways/AdminGateway.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace model;
+
+class AdminGateway 
+{
+    private \PDO $con;
+
+    public function __construct(\PDO $con)
+    {
+        $this->con=$con;
+    }
+
+    public function login(string $username, string $password): bool
+    {
+        $sql = "SELECT * FROM admin WHERE username=:username";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':username', $username);
+        $stmt->execute();
+        $result = $stmt->fetch();
+        if ($result && password_verify($password, $result['password'])) {
+            return true;
+        }
+        return false;
+    }
+    public function getHashedPassword(string $username): string
+    {
+        $sql = "SELECT password FROM user WHERE username=:username";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':username', $username);
+        $stmt->execute();
+        $result = $stmt->fetch();
+        return $result['password'];
+    }
+}
\ No newline at end of file
diff --git a/project/src/model/gateways/UserGateway.php b/project/src/model/gateways/UserGateway.php
new file mode 100644
index 0000000..7db3876
--- /dev/null
+++ b/project/src/model/gateways/UserGateway.php
@@ -0,0 +1,100 @@
+<?php
+
+namespace model;
+
+class UserGateway
+{
+    private \PDO $con;
+    private \PDOStatement $stmt;
+    public function __construct(\PDO $con, \PDOStatement $stmt)
+    {
+        $this->con=$con;
+        $this->stmt=$stmt;
+    }
+
+    public function login(string $username, string $password): bool
+    {
+        $sql = "SELECT * FROM user WHERE username=:username";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':username', $username);
+        $stmt->execute();
+        $result = $stmt->fetch();
+        if ($result && password_verify($password, $result['password'])) {
+            return true;
+        }
+        return false;
+    }
+    public function addUser(string $username, string $password): void
+    {
+        $sql = "INSERT INTO user (username, password) VALUES (:username, :password)";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':username', $username);
+        $stmt->bindValue(':password', $password);
+        $stmt->execute();
+    }
+    public function deleteUser(int $id): void
+    {
+        $sql = "DELETE FROM user WHERE id=:id";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':id', $id);
+        $stmt->execute();
+    }
+    public function updateUser(int $id, string $username, string $password): void
+    {
+        $sql = "UPDATE user SET username=:username, password=:password WHERE id=:id";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':id', $id);
+        $stmt->bindValue(':username', $username);
+        $stmt->bindValue(':password', $password);
+        $stmt->execute();
+    }
+    public function getUser(int $id): User
+    {
+        $sql = "SELECT * FROM user WHERE id=:id";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':id', $id);
+        $stmt->execute();
+        $result = $stmt->fetch();
+        return new User($result['id'], $result['username'], $result['password']);
+    }
+    public function getUsers(): array
+    {
+        $sql = "SELECT * FROM user";
+        $stmt = $this->con->prepare($sql);
+        $stmt->execute();
+        $result = $stmt->fetchAll();
+        $users = [];
+        foreach ($result as $user) {
+            $users[] = new User($user['id'], $user['username'], $user['password']);
+        }
+        return $users;
+    }
+    public function getHashedPasswordById(int $id): string
+    {
+        $sql = "SELECT password FROM user WHERE id=:id";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':id', $id);
+        $stmt->execute();
+        $result = $stmt->fetch();
+        return $result['password'];
+    }
+    public function getUserId(string $username): int
+    {
+        $sql = "SELECT id FROM user WHERE username=:username";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':username', $username);
+        $stmt->execute();
+        $result = $stmt->fetch();
+        return $result['id'];
+    }
+    public function getUserByUsernameAndPassword(string $username, string $password): User
+    {
+        $sql = "SELECT * FROM user WHERE username=:username AND password=:password";
+        $stmt = $this->con->prepare($sql);
+        $stmt->bindValue(':username', $username);
+        $stmt->bindValue(':password', $password);
+        $stmt->execute();
+        $result = $stmt->fetch();
+        return new User($result['id'], $result['username'], $result['password']);
+    }
+}
diff --git a/project/src/model/metier/Admin.php b/project/src/model/metier/Admin.php
new file mode 100644
index 0000000..30a40cb
--- /dev/null
+++ b/project/src/model/metier/Admin.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace model;
+
+class Admin extends User
+{
+    private string $email;
+
+    /**
+     * @param int $id
+     * @param string $username
+     * @param string $password
+     * @param string $email
+     */
+    public function __construct(int $id, string $username, string $password, string $email)
+    {
+        parent::__construct($id, $username, $password);
+        $this->email = $email;
+    }
+
+    /**
+     * @return string
+     */
+    public function getEmail(): string
+    {
+        return parent::getUsername();
+    }
+
+    /**
+     * @param string $email
+     */
+    public function setEmail(string $email): void
+    {
+        parent::setUsername($email);
+    }
+}
\ No newline at end of file
diff --git a/project/src/model/metier/Theme.php b/project/src/model/metier/Theme.php
index 5900456..e28e6ea 100644
--- a/project/src/model/metier/Theme.php
+++ b/project/src/model/metier/Theme.php
@@ -7,4 +7,5 @@ enum Theme
     case Maths;
     case Physics;
     case Chemistry;
+    case Biology;
 }
\ No newline at end of file
diff --git a/project/src/model/metier/User.php b/project/src/model/metier/User.php
new file mode 100644
index 0000000..5974c9e
--- /dev/null
+++ b/project/src/model/metier/User.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace model;
+
+class User
+{
+    private int $id;
+    private string $username;
+    private string $password;
+
+    /**
+     * @param int $id
+     * @param string $username
+     * @param string $password
+     */
+
+    public function __construct(int $id, string $username, string $password)
+    {
+        $this->id=$id;
+        $this->username=$username;
+        $this->password=$password;
+    }
+    public function getId(): int
+    {
+        return $this->id;
+    }
+    public function getUsername(): string
+    {
+        return $this->username;
+    }
+    public function setUsername(string $username): void
+    {
+        $this->username=$username;
+    }
+    public function setPassword(string $password): void
+    {
+        $this->password=$password;
+    }
+}
\ No newline at end of file