Add env variable

Author: ak-git

.env.template

@@ -0,0 +1,3 @@
+# see https://docs.docker.com/compose/environment-variables/variable-interpolation/
+# see https://docs.docker.com/reference/cli/docker/container/run/#env
+APP_GREETING='Greeting from .env'

README.md

@@ -102,6 +102,12 @@ docker stop helidon-se
 docker compose run -d --name helidon-se --rm helidon-se
 ```
 
+Use ```./.env``` file or overwrite as
+
+```shell
+APP_GREETING=Greet docker compose up -d
+```
+
 and follow ```-f``` logs
 
 ```shell

docker-compose.yaml

@@ -2,6 +2,8 @@ services:
   helidon-se:
     container_name: helidon-se
     image: a002k/helidon-se:latest
+    environment:
+      - APP_GREETING=${APP_GREETING:-'Greeting from docker-compose'}
     ports:
       - "8080:8080"
     networks: