<?php
// connect to MySQL database.
class Database {
    public $connection;

    public function __construct($config, $username, $password)
    {
        $dsn = 'mysql:'.http_build_query($config, '', ';');
        $this->connection  = new PDO($dsn, $username, $password, [PDO::ATTR_DEFAULT_FETCH_MODE=> PDO::FETCH_ASSOC]);
    }
    public function query($query, $params = []) {
        $statement = $this->connection->prepare($query);
        $statement->execute($params);
        return $statement;
    }
}