correct entry script bug and allow config from env file

- A bug in `entry` caused the script to not change into the directory correctly.
This was corrected by marking the script as bash rather than sh.
- `install.sh` now stops a running service before updating
- `docker-compose.yml` now assigns a consistent container name for the app
- `docker-compose.yml` now uses environment variables or a `.env` file to
  assign container name and port mappings if available
- updated readme file with better instructions

README.md

@@ -2,13 +2,39 @@
 
 Packaging and installation tools for Streamline's "Streamline EMR" application.
 
-## Usage
+## Building
 1. ensure you have docker access to this project's container registry on GitLab
 2. run `package.sh` to generate a new application package
 3. package will be stored to `build-packages/`
 
-## Notes
-- Example of running the app directly
-```bash
-docker run --rm -d --name streamline -p 3000:80 -p 6607:3306 -v ./data:/var/lib/mysql registry.gitlab.com/signalytic/client-external/streamline/streamline-emr:2.0
-```
+## Installing
+1. extract the generated archive file in a temporary folder on the target system
+2. run `install.sh`
+
+## Running
+### Production (systemd)
+On a production system, `systemd` will manage the lifecycle of the application, e.g.
+```
+# enable and start the the application service
+systemctl daemon-reload
+systemctl enable streamline-emr
+systemctl start streamline-emr
+
+# stop the application service
+systemctl stop streamline-emr
+
+# restart the application service
+systemctl restart streamline-emr
+```
+
+### Docker
+In a docker environment, the application must be started manually. This is done by running the `entry` script, for example:
+```
+/var/signalytic/clientapps/streamline/streamline-emr/entry
+```
+
+## Configuration
+Certain configuration options can be adjusted by setting environment variables or by defining these variables in a `.env` file stored in the same directory as the `docker-compose.yml` file. These variables are:
+`APP_PORTS`: port mapping for the web app server (default: `3000:80`)
+`DB_PORTS`: port mapping for the database server (default: `6607:3306`)
+`CONTAINER_NAME`: name of the application container (default: `streamline-emr`)