add build status; add sample Docker compose file

Author: deminy

README.md

@@ -1,5 +1,7 @@
 # Docker image for php 5.2 legacy projects
 
+[![Build Status](https://img.shields.io/docker/build/jrottenberg/ffmpeg.svg)](https://hub.docker.com/r/deminy/php-5.2/)
+
 This docker image is intended to work as a replacement for old legacy projects, running on old server.
 
 Features:
@@ -12,3 +14,17 @@ Features:
     * Enable PHP on the default site.
     * Allow [short open tag](http://php.net/manual/en/ini.core.php#ini.short-open-tag).
     * Various updates and fixes.
+
+# Sample Docker compose file
+
+```yaml
+version: '3'
+
+services:
+  app:
+    image: deminy/php-5.2
+    ports:
+      - "80:80"
+    volumes:
+      - ~/projects/example.com:/project
+```