diff --git a/Project/php/model/UserGateway.php b/Project/php/model/UserGateway.php
index 0b49896..3f22e37 100755
--- a/Project/php/model/UserGateway.php
+++ b/Project/php/model/UserGateway.php
@@ -16,35 +16,99 @@ class UserGateway
         $this->con = $con;
     }
 
-    public function findAllStudents() : array{
-        $query = "SELECT u.* FROM User_ u, Be b, Role_ r WHERE u.id=b.userID AND b.roleID=r.id AND r.name='student'";
+    public function findAllUsers() : array{
+        $query = "SELECT * FROM User_";
         $this->con->executeQuery($query, array());
         $results = $this->con->getResults();
         $tab = array();
         foreach ($results as $row)
-            $tab[] = new Student($row['id'], $row['email'], $row['name'], $row['surname'], $row['nickname'], $row['extraTime']);
+            $tab[] = new User($row['id'], $row['password'], $row['email'], $row['name'], $row['surname'], $row['nickname'], $row['image'], $row['extraTime'], $row['groupID']);
         return $tab;
     }
 
-    public function findStudentByName(string $name): array{
-        $query = "SELECT u.* FROM User_ u, Be b, Role_ r WHERE u.id=b.userID AND b.roleID=r.id AND r.name='student' AND u.name=:name";
+    public function findUserById(int $id) : array{
+        $query = "SELECT * FROM User_ WHERE id=:id";
+        $args = array(':id' => array($id, PDO::PARAM_INT));
+        $this->con->executeQuery($query, $args);
+        $results = $this->con->getResults();
+        $tab = array();
+        foreach ($results as $row)
+            $tab[] = new User($row['id'], $row['password'], $row['email'], $row['name'], $row['surname'], $row['nickname'], $row['image'], $row['extraTime'], $row['groupID']);
+        return $tab;
+    }
+
+    public function findUserByName(string $name) : array{
+        $query = "SELECT * FROM User_ WHERE name=:name";
         $args = array(':name' => array($name, PDO::PARAM_STR));
         $this->con->executeQuery($query, $args);
         $results = $this->con->getResults();
         $tab = array();
         foreach ($results as $row)
-            $tab[] = new Student($row['id'], $row['email'], $row['name'], $row['surname'], $row['nickname'], $row['extraTime']);
+            $tab[] = new User($row['id'], $row['password'], $row['email'], $row['name'], $row['surname'], $row['nickname'], $row['image'], $row['extraTime'], $row['groupID']);
         return $tab;
     }
 
-    public function findStudentBySurname(string $surname): array{
-        $query = "SELECT u.* FROM User_ u, Be b, Role_ r WHERE u.id=b.userID AND b.roleID=r.id AND r.name='student' AND u.surname=:surname";
+    public function findUserBySurname(string $surname) : array{
+        $query = "SELECT * FROM User_ WHERE surname=:surname";
         $args = array(':surname' => array($surname, PDO::PARAM_STR));
         $this->con->executeQuery($query, $args);
         $results = $this->con->getResults();
         $tab = array();
         foreach ($results as $row)
-            $tab[] = new Student($row['id'], $row['email'], $row['name'], $row['surname'], $row['nickname'], $row['extraTime']);
+            $tab[] = new User($row['id'], $row['password'], $row['email'], $row['name'], $row['surname'], $row['nickname'], $row['image'], $row['extraTime'], $row['groupID']);
         return $tab;
     }
+
+    public function findUserByNickname(string $nickname) : array{
+        $query = "SELECT * FROM User_ WHERE nickname=:nickname";
+        $args = array(':nickname' => array($nickname, PDO::PARAM_STR));
+        $this->con->executeQuery($query, $args);
+        $results = $this->con->getResults();
+        $tab = array();
+        foreach ($results as $row)
+            $tab[] = new User($row['id'], $row['password'], $row['email'], $row['name'], $row['surname'], $row['nickname'], $row['image'], $row['extraTime'], $row['groupID']);
+        return $tab;
+    }
+
+    public function isAdmin(int $id):bool {
+        $query = "SELECT * FROM Be WHERE userID=:id AND roleID=1";
+        $args = array(':id' => array($id, PDO::PARAM_INT));
+        $this->con->executeQuery($query, $args);
+        return !empty($this->con->getResults());
+    }
+
+    public function addUser(string $password, string $email, string $name, string $surname, string $nickname, string $image, bool $extraTime, int $group, array $roles): int {
+        $query = "INSERT INTO User_ VALUES (NULL, :password, :email, :name, :surname, :nickname, :image, :extraTime, :group)";
+        $args = array(':password' => array($password, PDO::PARAM_STR),
+            ':email' => array($email, PDO::PARAM_STR),
+            ':name' => array($name, PDO::PARAM_STR),
+            ':surname' => array($surname, PDO::PARAM_STR),
+            ':nickname' => array($nickname, PDO::PARAM_STR),
+            ':image' => array($image, PDO::PARAM_STR),
+            ':extraTime' => array($extraTime, PDO::PARAM_BOOL),
+            ':group' => array($group, PDO::PARAM_INT));
+        $this->con->executeQuery($query, $args);
+        $userID = $this->con->lastInsertId();
+
+        foreach ($roles as $role) {
+            $query = "INSERT INTO Be VALUES (:userID, :roleID)";
+            $args = array(':userID' => array($userID, PDO::PARAM_INT),
+                ':roleID' => array($role, PDO::PARAM_INT));
+            $this->con->executeQuery($query, $args);
+        }
+
+        return $userID;
+    }
+
+    public function RemoveUser(int $id) {
+        $query="DELETE FROM Vocabulary WHERE creator=:id";
+        $args = array(':id' => array($id, PDO::PARAM_INT));
+        $this->con->executeQuery($query, $args);
+
+        $query="DELETE FROM Be WHERE userID=:id";
+        $this->con->executeQuery($query, $args);
+
+        $query="DELETE FROM User_ WHERE id=:id";
+        $this->con->executeQuery($query, $args);
+    }
 }
\ No newline at end of file