first commit

app/Model/userModel.php

@@ -0,0 +1,31 @@
+<?php
+namespace Blog\Model;
+
+use Blog\Entity\user;
+use Blog\Database\database;
+use PDO;
+
+class UserModel {
+  private $db;
+
+  public function __construct() {
+    $this->db = Database::getConnection();
+  }
+
+  public function getUserByUsername(string $username):?User {
+    $query = $this->db->prepare(<<<SQL
+      SELECT id, username, password
+      FROM users
+      WHERE username = :username
+      LIMIT 1
+    SQL);
+    $query->bindParam(':username', $username);
+    $query->execute();
+
+    $row = $query->fetchObject();
+    if(!$row)
+      return null;
+
+    return new User($row->id, $row->username, $row->password);
+  }
+}