Site/dev: allow overriding the podman/docker binaries detection (apache#2051)

The scripts in the `bin/` directory are built to work with both Docker and podman. There are nuances in how both behave, especially wrt docker/podman-compose. Some local environment specifics require the use of `podman-compose`, others the use of `docker-compose`. The default behavior is to prefer the `podman` and `podman-compose` binaries, if those exist and fall back to `docker` and `docker-compose`. Some setups using podman however require the use of `docker-compose` even if `podman-compose` is installed. This may manifest in an error message stating that `--userns` and `--pod` cannot be used together. In that case create a file `.user-settings` in the `site/` folder and add these two lines:
```bash
DOCKER=docker
COMPOSE=docker-compose
```

Author: snazy

site/.gitignore

@@ -17,6 +17,8 @@
 # under the License.
 #
 
+.user-settings
+
 content/releases/
 
 # Created/generated when running Hugo on the local host

site/README.md

@@ -35,6 +35,21 @@ Then point your browser to http://localhost:1313/
 Then edit files from your IDE - you will see the changes in your browser. When changing the site structure,
 it is often necessary to restart Hugo - just run `site/bin/run-hugo-in-docker.sh` again. 
 
+## Dealing with `--userns and --pod cannot be used together` errors
+
+The scripts in the `bin/` directory are built to work with both Docker and podman. There are nuances in how
+both behave, especially wrt docker/podman-compose. Some local environment specifics require the use of
+`podman-compose`, others the use of `docker-compose`. The default behavior is to prefer the `podman` and
+`podman-compose` binaries, if those exist and fall back to `docker` and `docker-compose`. Some setups using
+podman however require the use of `docker-compose` even if `podman-compose` is installed. This may manifest
+in an error message stating that `--userns` and `--pod` cannot be used together. In that case create a file
+`.user-settings` in the `site/` folder and add these two lines:
+```bash
+DOCKER=docker
+COMPOSE=docker-compose
+```
+
+
 # Building the static site
 
 ## Building a static site - served at http://localhost:8080/

site/bin/_hugo-docker-include.sh

@@ -17,8 +17,10 @@
 # under the License.
 #
 
-DOCKER="$(which podman > /dev/null && echo podman || echo docker)"
-COMPOSE="$(which podman-compose > /dev/null && echo podman-compose || echo docker-compose)"
+[[ -f site/.user-settings ]] && . site/.user-settings
+
+[[ -z ${DOCKER} ]] && DOCKER="$(which podman > /dev/null && echo podman || echo docker)"
+[[ -z ${COMPOSE} ]] && COMPOSE="$(which podman-compose > /dev/null && echo podman-compose || echo docker-compose)"
 
 # absolute path to the Polaris workspace, for the volume mount
 WORKSPACE="$(pwd)"