doc: update installing-upgrading.md regarding custom stylesheets

Author: aatkin

docs/installing-upgrading.md

@@ -54,15 +54,15 @@ Generally the database must be started, migrated and populated first.
 
 ### Option 1: Run REMS from Docker Hub
 
-This tries to fetch the latest REMS image from Docker Hub. This uses the default `docker-compose.yml` file.
+This tries to fetch the latest REMS image from Docker Hub. This uses the default `docker-compose.yml` file. It doesn't include files referred to in default config, such as `example-theme/extra-styles.css`, which includes default fonts.
 
     docker-compose up -d db
     docker-compose run --rm -e CMD="migrate;test-data" app
     docker-compose up -d app
 
 ### Option 2: Use config file simple-config.edn instead of environment variables
 
-The other build file `docker-compose-config.yml` shows how to configure an external config file named `simple-config.edn`. The file is provided through a volume mounted to the correct place in the container. Don't forget to map all the files you refer to in the config (like `theme.edn`) with similar volumes. Alternatively, you could build your own image on top of our base image, so that it includes the files inside. We prefer to have one image that is same in all environments and use mappings to provide the varying data (config).
+The other build file `docker-compose-config.yml` shows how to configure an external config file named `simple-config.edn`, and custom stylesheet file named `extra-styles.css` which includes default fonts. The files are provided through volumes mounted to the correct place in the container. Don't forget to map all the files you refer to in the config (like `theme.edn`) with similar volumes. Alternatively, you could build your own image on top of our base image, so that it includes the files inside. We prefer to have one image that is same in all environments and use mappings to provide the varying data (config).
 
     docker-compose -f docker-compose-config.yml up -d db
     docker-compose -f docker-compose-config.yml run --rm -e CMD="migrate;test-data" app