Added docker-compose files.

README.md

@@ -8,7 +8,11 @@ Clone this repo and then:
     cd docker-Postfix
     sudo docker build -t postfix .
 
-You can also find a prebuilt docker image from [Docker Hub](https://registry.hub.docker.com/u/juanluisbaptiste/postfix/), which can be pulled with this command:
+Or you can use the provided [docker-compose](https://github.com/juanluisbaptiste/docker-postfix/blob/master/docker-compose.yml) files:
+
+    sudo docker-compose -f docker-compose.yml -f docker-compose.dev.yml build
+
+For more information on using multiple compose files [see here](https://docs.docker.com/compose/production/). You can also find a prebuilt docker image from [Docker Hub](https://registry.hub.docker.com/u/juanluisbaptiste/postfix/), which can be pulled with this command:
 
     sudo docker pull juanluisbaptiste/postfix:latest
 
@@ -38,8 +42,11 @@ If you are going to use this container from other docker containers then it's be
            -e SMTP_PASSWORD=XXXXXXXX \
            -e SERVER_HOSTNAME=helpdesk.mycompany.com \           
            juanluisbaptiste/postfix
-    
-    
+
+Or if you can start the service using the provided [docker-compose](https://github.com/juanluisbaptiste/docker-postfix/blob/master/docker-compose.yml) file for production use:
+
+    sudo docker-compose up -d
+
 #### A note about using gmail as a relay
 
 Since last year, Gmail by default [does not allow email clients that don't use OAUTH 2](http://googleonlinesecurity.blogspot.co.uk/2014/04/new-security-measures-will-affect-older.html) 

docker-compose.dev.yml

@@ -0,0 +1,6 @@
+version: '2'
+services:
+  postfix:
+    build:
+      context: .
+      dockerfile: Dockerfile

docker-compose.yml

@@ -0,0 +1,11 @@
+version: '2'
+services:
+  postfix:
+    image: juanluisbaptiste/postfix:latest
+    expose:
+    - "25"
+    env_file:
+      - ../../credentials-smtp.env
+    restart: always
+    volumes:
+     - "/etc/localtime:/etc/localtime:ro"