Change installation process in the readme

Fixes #33

Author: Edmundo Alvarez

README.md

@@ -9,10 +9,17 @@ __Use this paragraph to enter a description of your plugin.__
 Installation
 ------------
 
-[Download the plugin](https://github.com/graylog-plugin-pipeline-processor/releases)
-and place the `.jar` file in your Graylog plugin directory. The plugin directory
-is the `plugins/` folder relative from your `graylog-server` directory by default
-and can be configured in your `graylog.conf` file.
+This plugin is included by default in Graylog 2.0 tarballs and packages,
+so you do not need to install it by hand.
+
+For now we do not provide individual releases of the plugin, but you can still
+find it inside the Graylog tarball available in the [downloads page](https://www.graylog.org/download/).
+The plugin is located in the `plugin` directory of the tarball.
+
+Once you get the `.jar` file from the tarball, place it in your Graylog plugin
+directory. The plugin directory is the `plugins/` folder relative from your
+`graylog-server` directory by default and can be configured in your
+`graylog.conf` file.
 
 Restart `graylog-server` and you are done.