update var name, update readme and instructions

Author: aptalca

README.md

@@ -125,6 +125,7 @@ Once registered you can define the dockerfile to use with `-f Dockerfile.aarch64
 
 ## Versions
 
+* **31.07.20:** - Add support for global env var `DOCKER_COMPOSE_IMAGE_TAG` in the `run.sh` script.
 * **06.07.20:** - Publish docker-compose and docker-cli binaries in Github releases.
 * **01.07.20:** - Release alpine based images at `alpine` tag.
 * **04.06.20:** - Bump docker-cli to 19.03.8, auto-detect python3 version.

readme-vars.yml

@@ -131,6 +131,7 @@ full_custom_readme: |
 
   ## Versions
 
+  * **31.07.20:** - Add support for global env var `DOCKER_COMPOSE_IMAGE_TAG` in the `run.sh` script.
   * **06.07.20:** - Publish docker-compose and docker-cli binaries in Github releases.
   * **01.07.20:** - Release alpine based images at `alpine` tag.
   * **04.06.20:** - Bump docker-cli to 19.03.8, auto-detect python3 version.

run.sh

@@ -13,12 +13,16 @@
 # You can add additional volumes (or any docker run options) using
 # the $COMPOSE_OPTIONS environment variable.
 #
+# You can set a specific image tag from Docker Hub, such as "1.26.2-ls9", or "alpine"
+# using the $DOCKER_COMPOSE_IMAGE_TAG environment variable (defaults to "latest")
+#
 
 
 set -e
 
-DOCKER_COMPOSE_CONTAINER_VERSION="${DOCKER_COMPOSE_CONTAINER_VERSION-latest}" # can be set to a specific version tag from docker hub, such as "1.25.5", or "alpine"
-IMAGE="linuxserver/docker-compose:$DOCKER_COMPOSE_CONTAINER_VERSION"
+# set image tag to latest if not globally set
+DOCKER_COMPOSE_IMAGE_TAG="${DOCKER_COMPOSE_IMAGE_TAG:-latest}"
+IMAGE="linuxserver/docker-compose:$DOCKER_COMPOSE_IMAGE_TAG"
 
 # Setup options for connecting to docker host
 if [ -z "$DOCKER_HOST" ]; then