accommodating tagged images (#22)

Dockerfile

@@ -25,7 +25,7 @@ RUN echo deb http://packages.elasticsearch.org/elasticsearch/2.x/debian stable m
 
 RUN apt-get update -qq \
  && apt-get install -qqy \
-		elasticsearch \
+		elasticsearch=2.2.0 \
 		openjdk-7-jdk \
  && apt-get clean
 

README.md

@@ -2,18 +2,25 @@
 
 [![](https://badge.imagelayers.io/sebp/elk:latest.svg)](https://imagelayers.io/?images=sebp/elk:latest 'Get your own badge on imagelayers.io')
 
-This Docker image provides a convenient centralised log server and log management web interface, by packaging Elasticsearch (version 2.2.0), Logstash (version 2.2.0), and Kibana (version 4.4.0), collectively known as ELK.
+This Docker image provides a convenient centralised log server and log management web interface, by packaging Elasticsearch, Logstash, and Kibana, collectively known as ELK.
 
-**Note** – The last image using the Elasticsearch 1.x and Logstash 1.x branches is also available (the versions of the ELK components in that image are Elasticsearch 1.7.3, Logstash 1.5.5, and Kibana 4.1.2). See the documentation page for more information.
+The following tags are available:
+
+- `es220_l220_k440`, `latest`: Elasticsearch 2.2.0, Logstash 2.2.0, and Kibana 4.4.0.
+
+- `E1L1K4`: Elasticsearch 1.7.3, Logstash 1.5.5, and Kibana 4.1.2.
+
+**Note** – See the documentation page for more information on pulling specific combinations of versions of Elasticsearch, Logstash and Kibana.
 
 ### Documentation
 
 See the [ELK Docker image documentation web page](http://elk-docker.readthedocs.org/) for complete instructions on how to use this image.
 
+### Docker Hub
+
+This image is hosted on Docker Hub at [https://hub.docker.com/r/sebp/elk/](https://hub.docker.com/r/sebp/elk/).
+
 ### About
 
 Written by [Sébastien Pujadas](https://pujadas.net), released under the [Apache 2 license](https://www.apache.org/licenses/LICENSE-2.0).
 
-### Docker Hub
-
-This image is hosted on Docker Hub at https://hub.docker.com/r/sebp/elk/

docs/index.md

@@ -5,6 +5,7 @@ This web page documents how to use the [sebp/elk](https://hub.docker.com/r/sebp/
 ### Contents ###
 
 - [Installation](#installation)
+	- [Pulling specific version combinations](#specific-version-combinations)
 - [Usage](#usage)
 	- [Running the container using Docker Compose](#running-with-docker-compose)
 	- [Creating a dummy log entry](#creating-dummy-log-entry)
@@ -38,7 +39,15 @@ To pull this image from the [Docker registry](https://hub.docker.com/r/sebp/elk/
 
 **Note** – This image has been built automatically from the source files in the [source Git repository on GitHub](https://github.com/spujadas/elk-docker). If you want to build the image yourself, see the [Building the image](#building-image) section below.
 
-**Note** – The last image using the Elasticsearch 1.x and Logstash 1.x branches can be pulled using `sudo docker pull sebp/elk:E1L1K4`. The versions of the ELK components in that image are: Elasticsearch 1.7.3, Logstash 1.5.5, and Kibana 4.1.2.
+### Pulling specific version combinations <a name="specific-version-combinations"></a> 
+
+Specific version combinations of Elasticsearch, Logstash and Kibana can be pulled by using tags.
+
+For instance, the image containing Elasticsearch 1.7.3, Logstash 1.5.5, and Kibana 4.1.2 (which is the last image using the Elasticsearch 1.x and Logstash 1.x branches) bears the tag `E1L1K4`, and can therefore be pulled using `sudo docker pull sebp/elk:E1L1K4`.
+
+The available tags are listed on [Docker Hub's sebp/elk image page](https://hub.docker.com/r/sebp/elk/) or GitHub repository page.
+
+By default, if not tag is indicated (or if using the tag `latest`), the latest version of the image will be pulled.
 
 ## Usage <a name="usage"></a>