README.md some error

[ctam]

README.md

warden := ladon.Ladon{
        Manager: manager.NewMemoryManager(),
        AuditLogger: ladon.AuditLoggerInfo{}
    }

should be

warden := ladon.Ladon{
        Manager: manager.NewMemoryManager(),
        AuditLogger: &ladon.AuditLoggerInfo{}
    }

[hackerman]

Feel free to propose a change using a PR!