[DOCS] Adds getting started content based on the template (#2141)

Co-authored-by: Fernando Briano <fernando@picandocodigo.net>

docs/getting-started.asciidoc

@@ -0,0 +1,141 @@
+[[getting-started-ruby]]
+== Getting started
+
+This page guides you through the installation process of the Ruby client, shows 
+you how to instantiate the client, and how to perform basic Elasticsearch 
+operations with it.
+
+[discrete]
+=== Requirements
+
+A currently maintained version of Ruby (3.0+) or JRuby (9.3+).
+
+[discrete]
+=== Installation 
+
+To install the latest version of the client, run the following command:
+
+[source,shell]
+--------------------------
+gem install elasticsearch
+--------------------------
+
+Refer to the <<ruby-install>> page to learn more.
+
+
+[discrete]
+=== Connecting
+
+You can connect to the Elastic Cloud using an API key and the Elasticsearch 
+endpoint. 
+
+[source,rb]
+----
+client = Elasticsearch::Client.new(
+  cloud_id: '<CloudID>',
+  api_key: '<ApiKey>'
+)
+----
+
+Your Elasticsearch endpoint can be found on the **My deployment** page of your 
+deployment:
+
+image::images/es_endpoint.jpg[alt="Finding Elasticsearch endpoint",align="center"]
+
+You can generate an API key on the **Management** page under Security.
+
+image::images/create_api_key.png[alt="Create API key",align="center"]
+
+For other connection options, refer to the <<connecting>> section.
+
+
+[discrete]
+=== Operations
+
+Time to use Elasticsearch! This section walks you through the basic, and most 
+important, operations of Elasticsearch. For more operations and more advanced 
+examples, refer to the <<examples>> page.
+
+
+[discrete]
+==== Creating an index
+
+This is how you create the `my_index` index:
+
+[source,rb]
+----
+client.indices.create(index: 'my_index')
+----
+
+
+[discrete]
+==== Indexing documents
+
+This is a simple way of indexing a document:
+
+[source,rb]
+----
+document = { name: 'elasticsearch-ruby' }
+response = client.index(index: 'my_index', body: document)
+# You can get the indexed document id with:
+response['_id']
+=> "PlgIDYkBWS9Ngdx5IMy-"
+id = response['_id']
+----
+
+
+[discrete]
+==== Getting documents
+
+You can get documents by using the following code:
+
+[source,rb]
+----
+client.get(index: 'my_index', id: id)
+----
+
+
+[discrete]
+==== Searching documents
+
+This is how you can create a single match query with the Ruby client: 
+
+[source,rb]
+----
+client.search(index: 'my_index', body: { query: { match_all: {} } })
+----
+
+
+[discrete]
+==== Updating documents
+
+This is how you can update a document, for example to add a new field:
+
+[source,rb]
+----
+client.update(index: 'my_index', id: id, body: { doc: { language: 'Ruby' } })
+----
+
+
+[discrete]
+==== Deleting documents
+
+[source,rb]
+----
+client.delete(index: 'my_index', id: id)
+----
+
+
+[discrete]
+==== Deleting an index
+
+[source,rb]
+----
+client.indices.delete(index: 'my_index')
+----
+
+
+[discrete]
+== Further reading
+
+* Use <<Helpers>> for a more confortable experience with the APIs.

docs/index.asciidoc

@@ -6,6 +6,8 @@ include::{asciidoc-dir}/../../shared/attributes.asciidoc[]
 
 include::overview.asciidoc[]
 
+include::getting-started.asciidoc[]
+
 include::installation.asciidoc[]
 
 include::connecting.asciidoc[]

docs/overview.asciidoc

@@ -5,6 +5,9 @@ The `elasticsearch` http://rubygems.org/gems/elasticsearch[Rubygem] provides a l
 
 More documentation is hosted in https://github.com/elastic/elasticsearch-ruby[Github] and http://rubydoc.info/gems/elasticsearch[RubyDoc].
 
+Refer to the <<getting-started-ruby>> page for a step-by-step quick start with
+the Ruby client.
+
 [discrete]
 === Features