public function checkDatabaseConnection(Request $request)
{
    //update the config
     config(['database.connections.mysql' => [
        'host'     => $request->host,
        'username' => $request->username,
        'password' => $request->password
    ]]);

    //Check the credentials by calling PDO
    try {
        DB::connection()->getPdo();
    } catch (Exception $e) {
        return redirect()->back()->withErrors(["connection" => "Could not connect to the database.  Please check your input."]);
    }
}