Docs: make the welcome page more obvious

Closes #31.

(cherry picked from commit ab3cde3)

Author: dadoonet

.gitignore

@@ -10,3 +10,4 @@
 /.classpath
 *.vmoptions
 .local-execution-hints.log
+plugin_tools

README.md

@@ -3,22 +3,30 @@ Google Compute Engine Cloud Plugin for Elasticsearch
 
 The GCE Cloud plugin allows to use GCE API for the unicast discovery mechanism.
 
-In order to install the plugin, simply run: `bin/plugin -install elasticsearch/elasticsearch-cloud-gce/2.1.1`.
+In order to install the plugin, run: 
 
-* For master elasticsearch versions, look at [master branch](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/master).
-* For 1.3.x elasticsearch versions, look at [es-1.3 branch](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/es-1.3).
-* For 1.2.x elasticsearch versions, look at [es-1.2 branch](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/es-1.2).
-* For 1.1.x elasticsearch versions, look at [es-1.1 branch](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/es-1.1).
-* For 1.0.x elasticsearch versions, look at [es-1.0 branch](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/es-1.0).
-* For 0.90.x elasticsearch versions, look at [es-0.90 branch](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/es-0.90).
+```sh
+bin/plugin -install elasticsearch/elasticsearch-cloud-gce/2.2.0
+```
 
-|       GCE Cloud Plugin     |    elasticsearch    |   gce api    | Release date |
-|----------------------------|---------------------|--------------|:------------:|
-| 3.0.0-SNAPSHOT             | master              |  1.18.0-rc   |  XXXX-XX-XX  |
+You need to install a version matching your Elasticsearch version:
 
-Please read documentation relative to the version you are using:
+|       Elasticsearch    | Azure Cloud Plugin|                                                             Docs                                                                   |
+|------------------------|-------------------|------------------------------------------------------------------------------------------------------------------------------------|
+|    master              | Build from source | See below                                                                                                                          |
+|    es-1.3              | Build from source | [2.3.0-SNAPSHOT](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/es-1.3/#google-compute-engine-cloud-plugin-for-elasticsearch)|
+|    es-1.2              |     2.2.0         | [2.2.0](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/v2.2.0/#google-compute-engine-cloud-plugin-for-elasticsearch)|
+|    es-1.1              |     2.1.2         | [2.1.2](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/v2.1.2/#google-compute-engine-cloud-plugin-for-elasticsearch)|
+|    es-1.0              |     2.0.1         | [2.0.1](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/v2.0.1/#google-compute-engine-cloud-plugin-for-elasticsearch)|
+|    es-0.90             |     1.3.0         | [1.3.0](https://github.com/elasticsearch/elasticsearch-cloud-gce/tree/v1.3.0/#google-compute-engine-cloud-plugin-for-elasticsearch)|
 
-* [3.0.0-SNAPSHOT](https://github.com/elasticsearch/elasticsearch-cloud-gce/blob/master/README.md)
+To build a `SNAPSHOT` version, you need to build it with Maven:
+
+```bash
+mvn clean install
+plugin --install cloud-azure \ 
+       --url file:target/releases/elasticsearch-cloud-gce-X.X.X-SNAPSHOT.zip
+```
 
 
 Google Compute Engine Virtual Machine Discovery