Update ruby doc with the aws-sdk gem usage

Since I'm using ceph with the `aws-sdk` gem (https://github.com/aws/aws-sdk-ruby) instead `aws-s3` (https://github.com/marcel/aws-s3) because the aws-s3 have a trouble with the new active support (marcel/aws-s3#98) (and the downgrade active-support wasn't a option), I proposed change the doc to receive the usage instructions with the aws-sdk gem.

I used ceph with aws-sdk gem with this commands. 

Thanks so much

doc/radosgw/s3/ruby.rst

@@ -1,7 +1,194 @@
 .. _ruby:
 
-Ruby S3 Examples
-================
+Ruby S3 Examples (aws-sdk gem ~>2)
+==================================
+
+Settings
+---------------------
+
+You can setup the connection on global way:
+
+.. code-block:: ruby
+
+	Aws.config.update(
+		endpoint: 'https://objects.dreamhost.com.',
+		access_key_id: 'my-access-key',
+		secret_access_key: 'my-secret-key',
+		force_path_style: true, 
+		region: 'us-east-1'
+	)
+
+
+and instantiate a client object:
+
+.. code-block:: ruby
+
+    	s3_client = Aws::S3::Client.new
+
+Listing Owned Buckets
+---------------------
+
+This gets a list of buckets that you own.
+This also prints out the bucket name and creation date of each bucket.
+
+.. code-block:: ruby
+
+	s3_client.list_buckets.buckets.each do |bucket|
+		puts "#{bucket.name}\t#{bucket.creation_date}"
+	end
+
+The output will look something like this::
+
+   mahbuckat1	2011-04-21T18:05:39.000Z
+   mahbuckat2	2011-04-21T18:05:48.000Z
+   mahbuckat3	2011-04-21T18:07:18.000Z
+
+
+Creating a Bucket
+-----------------
+
+This creates a new bucket called ``my-new-bucket``
+
+.. code-block:: ruby
+
+	s3_client.create_bucket(bucket: 'my-new-bucket')
+
+If you want a private bucket: 
+
+`acl` option accepts: # private, public-read, public-read-write, authenticated-read
+
+.. code-block:: ruby
+
+	s3_client.create_bucket(bucket: 'my-new-bucket', acl: 'private')
+
+
+Listing a Bucket's Content
+--------------------------
+
+This gets a list of hashes with the contents of each object
+This also prints out each object's name, the file size, and last
+modified date.
+
+.. code-block:: ruby
+
+	s3_client.get_objects(bucket: 'my-new-bucket').contents.each do |object|
+		puts "#{object.key}\t#{object.size}\t#{object.last-modified}"
+	end
+
+The output will look something like this if the bucket has some files::
+
+   myphoto1.jpg	251262	2011-08-08T21:35:48.000Z
+   myphoto2.jpg	262518	2011-08-08T21:38:01.000Z
+
+
+Deleting a Bucket
+-----------------
+.. note::
+   The Bucket must be empty! Otherwise it won't work!
+
+.. code-block:: ruby
+
+	s3_client.delete_bucket(bucket: 'my-new-bucket')
+
+
+Forced Delete for Non-empty Buckets
+-----------------------------------
+First, you need to clear the bucket:
+
+.. code-block:: ruby
+
+	Aws::S3::Bucket.new('my-new-bucket', client: s3_client).clear!
+	
+after, you can destroy the bucket
+
+.. code-block:: ruby
+
+	s3_client.delete_bucket(bucket: 'my-new-bucket')
+
+
+Creating an Object
+------------------
+
+This creates a file ``hello.txt`` with the string ``"Hello World!"``
+
+.. code-block:: ruby
+
+	s3_client.put_object(
+		key: 'hello.txt',
+		body: 'Hello World!',
+		bucket: 'my-new-bucket',
+		content_type: 'text/plain'
+	)
+
+
+Change an Object's ACL
+----------------------
+
+This makes the object ``hello.txt`` to be publicly readable, and ``secret_plans.txt``
+to be private.
+
+.. code-block:: ruby
+
+	s3_client.put_object_acl(bucket: 'my-new-bucket', key: 'hello.txt', acl: 'public-read')
+
+	s3_client.put_object_acl(bucket: 'my-new-bucket', key: 'private.txt', acl: 'private')
+
+
+Download an Object (to a file)
+------------------------------
+
+This downloads the object ``poetry.pdf`` and saves it in
+``/home/larry/documents/``
+
+.. code-block:: ruby
+	s3_client.get_object(bucket: 'my-new-bucket', key: 'poetry.pdf', response_target: '/home/larry/documents/poetry.pdf')
+
+
+Delete an Object
+----------------
+
+This deletes the object ``goodbye.txt``
+
+.. code-block:: ruby
+
+	s3_client.delete_object(key: 'goodbye.txt', bucket: 'my-new-bucket')
+
+
+Generate Object Download URLs (signed and unsigned)
+---------------------------------------------------
+
+This generates an unsigned download URL for ``hello.txt``. This works
+because we made ``hello.txt`` public by setting the ACL above.
+This then generates a signed download URL for ``secret_plans.txt`` that
+will work for 1 hour. Signed download URLs will work for the time
+period even if the object is private (when the time period is up, the
+URL will stop working).
+
+.. code-block:: ruby
+
+	puts Aws::S3::Object.new(
+		key: 'hello.txt',
+		bucket_name: 'my-new-bucket',
+		client: s3_client
+	).public_url
+
+	puts Aws::S3::Object.new(
+		key: 'secret_plans.txt',
+		bucket_name: 'hermes_ceph_gem',
+		client: s3_client
+	).presigned_url(:get, expires_in: 60 * 60)
+
+The output of this will look something like::
+
+   http://objects.dreamhost.com/my-bucket-name/hello.txt
+   http://objects.dreamhost.com/my-bucket-name/secret_plans.txt?Signature=XXXXXXXXXXXXXXXXXXXXXXXXXXX&Expires=1316027075&AWSAccessKeyId=XXXXXXXXXXXXXXXXXXX
+
+.. _`Aws::S3`: http://docs.aws.amazon.com/sdkforruby/api/Aws/S3/Client.html
+
+
+
+Ruby S3 Examples (aws-s3 gem)
+=============================
 
 Creating a Connection
 ---------------------