Replace the single user (defined in /data/config.php) with a multi user management thing

services/UsersService.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace Grocy\Services;
+
+class UsersService extends BaseService
+{
+	public function CreateUser(string $username, string $firstName, string $lastName, string $password)
+	{
+		$newUserRow = $this->Database->users()->createRow(array(
+			'username' => $username,
+			'first_name' => $firstName,
+			'last_name' => $lastName,
+			'password' => password_hash($password, PASSWORD_DEFAULT)
+		));
+		$newUserRow->save();
+	}
+
+	public function EditUser(int $userId, string $username, string $firstName, string $lastName, string $password)
+	{
+		if (!$this->UserExists($userId))
+		{
+			throw new \Exception('User does not exist');
+		}
+
+		$user = $this->Database->users($userId);
+		$user->update(array(
+			'username' => $username,
+			'first_name' => $firstName,
+			'last_name' => $lastName,
+			'password' => password_hash($password, PASSWORD_DEFAULT)
+		));
+	}
+
+	public function DeleteUser($userId)
+	{
+		$row = $this->Database->users($args['userId']);
+		$row->delete();
+		$success = $row->isClean();
+		return $this->ApiResponse(array('success' => $success));
+	}
+
+	private function UserExists($userId)
+	{
+		$userRow = $this->Database->users()->where('id = :1', $userId)->fetch();
+		return $userRow !== null;
+	}
+}