update README

Author: petitphp

README.md

@@ -1 +1,21 @@
 # FacetWP - P2P
+
+## Before updating
+
+This version is not compatible with P2P facets created with previous version of this plugin. You will need to recreate and re-run the indexing process.
+
+## Description
+
+This plugin add two new type of sources for your facets, Posts to Posts (P2P) connections and their metas.
+
+## Installation
+
+### Requirements
+
+* FacetWP 2.0.4 or greater
+
+### Installation
+
+1. Unpack the download-package.
+2. Upload the files to the /wp-content/plugins/ directory.
+3. Activate the plugin