update readme for release choice

add specific release choice

README.md

@@ -2,7 +2,7 @@
 
 [![](https://images.microbadger.com/badges/version/diouxx/glpi.svg)](http://microbadger.com/images/diouxx/glpi "Get your own version badge on microbadger.com") [![](https://images.microbadger.com/badges/image/diouxx/glpi.svg)](http://microbadger.com/images/diouxx/glpi "Get your own image badge on microbadger.com")
 
-Install and run an GLPI instance with docker
+Install and run an GLPI instance with docker.
 
 ## Deploy GLPI without database
 ```sh
@@ -32,6 +32,14 @@ docker run --name glpi --hostname glpi --link mysql:mysql --volumes-from glpi-da
 
 Enjoy :)
 
+## Deploy a specific release of GLPI
+Default, docker run will use the latest release of GLPI.
+For an usage on production environnement, it's recommanded to use the latest release.
+Here an example for release 9.1.6 :
+```sh
+docker run --name glpi --hostname glpi --link mysql:mysql --volumes-from glpi-data -p 80:80 --e "VERSION_GLPI=9.1.6" -d diouxx/glpi
+```
+
 ## Deploy with docker-compose
 
 To deploy with docker compose, you use *docker-compose.yml* and *mysql.env* file.