amazon web services - create empty folder S3 ruby SDK -

I want to create an empty folder in Amazon S3 using Ruby SDK. Ive read that there is no folder concept in S3, so to construct a folder theoretically you have only one empty object with an empty "/"

  s3 = Aws :: S3 :: Client new (region: 'EU-West-1', credentials: credits) s3.put_object (bucket: "my_bucket", key: "my_folder /")  

By doing this Creates an empty object on my bucket, but then if I try to upload a file like this:

  s3.put_object (bucket: "my_bucket", well Minister: "my_folder / myfile")  

It does not make a file in my final it keeps old empty object, and creates a folder and a file. Therefore the bucket structure is followed by two commands:

  my_bucket / my_folder my_folder / my_file  

Why is this happening? Why does this object repeat my_folder? How do I create an empty folder for later use?