Add pointer to env vars for customization

docs/home/installation.md

@@ -98,3 +98,23 @@ services:
 ### Dockerfile
 
 A `Dockerfile` is included within the GitHub repository for those who require it, although this is only suggested for those with knowledge of dockerfiles. The official Plex Meta Manager build is available on the [Dockerhub Website](https://hub.docker.com/r/meisnate12/plex-meta-manager).
+
+## Runtime flags and ENV vars
+
+Plex Meta Manager's behavior can be modified in a variety of ways using either runtime flags or environnment variables.  These flags and vars are detailed [here](environmental).
+
+For example, this docker-compose would create a container that runs immediately upon start (rather than waiting until 5AM), uses a particular config file, processes only overlays on only one library, and exits when done:
+```yaml
+version: "2.1"
+services:
+  plex-meta-manager:
+    image: meisnate12/plex-meta-manager
+    container_name: plex-meta-manager
+    environment:
+      - PMM_RUN=true
+      - PMM_CONFIG=/config/special-config.yml
+      - PMM_OVERLAYS=true
+      - PMM_LIBRARIES=Movies
+    volumes:
+      - /path/to/config:/config
+```