adding docker-compose.override.yml instead of simple docker-compose.yml

tried to explain that the use of docker-compose.override.yml is more benefitial as docker-compose.yml will get overwritten with the next pull

docs/installation-and-operations/configuration/database/README.md

@@ -22,7 +22,7 @@ Example:
 docker run -d ... -e DATABASE_URL=postgres://user:pass@host:port/dbname openproject/community:11
 ```
 
-If you run the Compose based docker stack, you can simply override the `DATABASE_URL` environment variable, and remove the `db` service from the `docker-compose.yml` file. Then you can restart the stack with:
+If you run the Compose based docker stack, you can simply override the `DATABASE_URL` environment variable, and remove the `db` service from the `docker-compose.yml` file. Be careful, because by pulling a new version `docker-compose.yml` might get replaced. Best practice is using the file `docker-compose.override.yml` instead. Then you can restart the stack with:
 
 ```
 docker-compose down

docs/installation-and-operations/installation/docker/README.md

@@ -50,7 +50,7 @@ docker-compose up -d
 
 After a while, OpenProject should be up and running on `http://localhost:8080`. The default username and password is login: `admin`, and password: `admin`.
 
-Note that the `docker-compose.yml` file present in the repository can be adjusted to your convenience. For instance you could mount specific configuration files, override environment variables, or switch off services you don't need. Please refer to the official [Docker Compose documentation](https://docs.docker.com/compose/extends/) for more details.
+Note that the `docker-compose.yml` file present in the repository can be adjusted to your convenience. With each pull it will be overwritten. Best practice is to use the file `docker-compose.override.yml` for that case. For instance you could mount specific configuration files, override environment variables, or switch off services you don't need. Please refer to the official [Docker Compose documentation](https://docs.docker.com/compose/extends/) for more details.
 
 You can stop the Compose stack by running:
 
@@ -64,8 +64,7 @@ You can stop and remove all containers by running:
 docker-compose down
 ```
 
-This will not remove your data which is persisted in named volumes, likely called `compose_opdata` (for attachments) and `compose_pgdata` (for the database). The exact name depends on the name of the directory where
-your `docker-compose.yml` file is stored (`compose` in this case).
+This will not remove your data which is persisted in named volumes, likely called `compose_opdata` (for attachments) and `compose_pgdata` (for the database). The exact name depends on the name of the directory where your `docker-compose.yml` and/or you `docker-compose.override.yml` files are stored (`compose` in this case).
 
 If you want to start from scratch and remove the exsiting data you will have to remove these volumes via
 `docker volume rm compose_opdata compose_pgdata`.

docs/installation-and-operations/operation/reconfiguring/README.md

@@ -26,7 +26,7 @@ The wizard will automatically set environment variables to be used by OpenProjec
 
 ## Docker installation
 
-For the Compose-based docker installation, you should update the `docker-compose.yml` file and add any [environment variable](../../configuration/environment) that you may require. Docker Compose supports [file overrides](https://docs.docker.com/compose/extends/) so you may also want to use that. Then simply issue the following command:
+For the Compose-based docker installation, you should not update the `docker-compose.yml` file as it refreshes with each pull, but use the file `docker-compose.override.yml` instead. There you could add any [environment variable](../../configuration/environment) that you may require. Docker Compose supports [file overrides](https://docs.docker.com/compose/extends/) so you may also want to use that. Then simply issue the following command:
 
 ```
 docker-compose up -d