chore: update README of docker-based templates

Author: phorcys420

registry/coder-labs/templates/docker-build/README.md

@@ -22,8 +22,19 @@ This template builds a custom Docker image from the included Dockerfile, allowin
 
 ### Infrastructure
 
-The VM you run Coder on must have a running Docker socket and the `coder` user must be added to the Docker group:
-
+#### Running Coder inside Docker
+If you installed Coder as a container within Docker, you will have to do the following things:
+- Make the the Docker socket available to the container
+  - **(recommended) Mount `/var/run/docker.sock` via `--mount`/`volume`**
+  - _(advanced) Restrict the Docker socket via https://github.com/Tecnativa/docker-socket-proxy_
+- Set `--group-add`/`group_add` to the GID of the Docker group on the **host** machine
+  - You can get the GID by running `getent group docker` on the **host** machine
+
+If you are using `docker-compose`, here is an example on how to do those things (don't forget to edit `group_add`!):
+https://github.com/coder/coder/blob/0bfe0d63aec83ae438bdcb77e306effd100dba3d/docker-compose.yaml#L16-L23
+
+#### Running Coder outside of Docker
+If you installed Coder as a system package, the VM you run Coder on must have a running Docker socket and the `coder` user must be added to the Docker group:
 ```sh
 # Add coder user to Docker group
 sudo adduser coder docker

registry/coder/templates/docker-devcontainer/README.md

@@ -14,11 +14,22 @@ Provision Devcontainers as [Coder workspaces](https://coder.com/docs/workspaces)
 
 ### Infrastructure
 
-Coder must have access to a running Docker socket, and the `coder` user must be a member of the `docker` group:
-
-```shell
+#### Running Coder inside Docker
+If you installed Coder as a container within Docker, you will have to do the following things:
+- Make the the Docker socket available to the container
+  - **(recommended) Mount `/var/run/docker.sock` via `--mount`/`volume`**
+  - _(advanced) Restrict the Docker socket via https://github.com/Tecnativa/docker-socket-proxy_
+- Set `--group-add`/`group_add` to the GID of the Docker group on the **host** machine
+  - You can get the GID by running `getent group docker` on the **host** machine
+
+If you are using `docker-compose`, here is an example on how to do those things (don't forget to edit `group_add`!):
+https://github.com/coder/coder/blob/0bfe0d63aec83ae438bdcb77e306effd100dba3d/docker-compose.yaml#L16-L23
+
+#### Running Coder outside of Docker
+If you installed Coder as a system package, the VM you run Coder on must have a running Docker socket and the `coder` user must be added to the Docker group:
+```sh
 # Add coder user to Docker group
-sudo usermod -aG docker coder
+sudo adduser coder docker
 
 # Restart Coder server
 sudo systemctl restart coder

registry/coder/templates/docker/README.md

@@ -16,8 +16,19 @@ Provision Docker containers as [Coder workspaces](https://coder.com/docs/workspa
 
 ### Infrastructure
 
-The VM you run Coder on must have a running Docker socket and the `coder` user must be added to the Docker group:
-
+#### Running Coder inside Docker
+If you installed Coder as a container within Docker, you will have to do the following things:
+- Make the the Docker socket available to the container
+  - **(recommended) Mount `/var/run/docker.sock` via `--mount`/`volume`**
+  - _(advanced) Restrict the Docker socket via https://github.com/Tecnativa/docker-socket-proxy_
+- Set `--group-add`/`group_add` to the GID of the Docker group on the **host** machine
+  - You can get the GID by running `getent group docker` on the **host** machine
+
+If you are using `docker-compose`, here is an example on how to do those things (don't forget to edit `group_add`!):
+https://github.com/coder/coder/blob/0bfe0d63aec83ae438bdcb77e306effd100dba3d/docker-compose.yaml#L16-L23
+
+#### Running Coder outside of Docker
+If you installed Coder as a system package, the VM you run Coder on must have a running Docker socket and the `coder` user must be added to the Docker group:
 ```sh
 # Add coder user to Docker group
 sudo adduser coder docker