adding variables for image tags

docker-compose.yml

@@ -3,7 +3,7 @@ version: "3"
 services:
   postgres:
     container_name: postgres_mattermost
-    image: postgres:alpine
+    image: postgres:${POSTGRES_IMAGE_TAG}
     restart: unless-stopped
     volumes:
       - ${POSTGRES_DATA_PATH}:/var/lib/postgresql/data
@@ -15,7 +15,7 @@ services:
 
   nginx:
     container_name: nginx_mattermost
-    image: nginx:alpine
+    image: nginx:${NGINX_IMAGE_TAG}
     restart: unless-stopped
     volumes:
       - ${NGINX_MATTERMOST_CONFIG}:/etc/nginx/conf.d/mattermost.conf:ro
@@ -32,7 +32,7 @@ services:
       - postgres
       - nginx
     container_name: mattermost
-    image: mattermost/mattermost-enterprise-edition:latest
+    image: mattermost/${MATTERMOST_IMAGE}:${MATTERMOST_IMAGE_TAG}
     restart: unless-stopped
     volumes:
       - ${MATTERMOST_CONFIG_PATH}:/mattermost/config:rw

env.example

@@ -1,6 +1,8 @@
 # Postrges settings
 ## Documentation for this image and available settings can be found on hub.docker.com
 ## https://hub.docker.com/_/postgres
+POSTGRES_IMAGE_TAG=alpine
+
 POSTGRES_USER=mmuser
 POSTGRES_PASSWORD=mmuser_password
 POSTGRES_DB=mattermost
@@ -14,6 +16,8 @@ POSTGRES_DATA_PATH=./data/postgres  # relative paths will work but absolute are
 
 ## Inside the container the uid and gid is 101. The folder owner can be set with
 ## `sudo chown -R 101:101 ./data/mattermost`.
+NGINX_IMAGE_TAG=alpine
+
 NGINX_MATTERMOST_CONFIG=./nginx/mattermost.conf
 NGINX_DHPARAMS_FILE=./nginx/dhparams4096.pem
 
@@ -33,6 +37,9 @@ MATTERMOST_LOGS_PATH=./data/mattermost/logs
 MATTERMOST_PLUGINS_PATH=./data/mattermost/plugins
 MATTERMOST_CLIENT_PLUGINS_PATH=./data/mattermost/client-plugins
 
+MATTERMOST_IMAGE=mattermost-enterprise-edition
+MATTERMOST_IMAGE_TAG=latest
+
 ## Configuration settings for Mattermost. Documentation on the variables and the settings itself can be found at
 ## https://docs.mattermost.com/administration/config-settings.html
 ## Keep in mind that variables set here will take precedence over the same setting in config.json. This includes