feat: Container runtime detection (#38)

bin/phpctl

@@ -9,9 +9,21 @@ fi
 PHP_VERSION=${PHP_VERSION:-82}
 PHPCTL_IMAGE=${PHPCTL_IMAGE:-opencodeco/phpctl:php$PHP_VERSION}
 PHPCTL_TTY=${PHPCTL_TTY:--it}
-PHPCTL_RUNTIME=${PHPCTL_RUNTIME:-docker}
+PHPCTL_RUNTIME=${PHPCTL_RUNTIME:-detect}
 PHPCTL_USER=${PHPCTL_USER:-root}
 
+if [ "${PHPCTL_RUNTIME}" == "detect" ]; then
+    PHPCTL_RUNTIME=
+    if command -v docker > /dev/null 2>&1; then
+        PHPCTL_RUNTIME=docker
+    elif command -v podman > /dev/null 2>&1; then
+        PHPCTL_RUNTIME=podman
+    else
+        echo "Could not find neither \"docker\" nor \"podman\", aborting"
+        exit 1
+    fi
+fi
+
 for file in "$PHPCTL_DIR"/src/*.sh; do
     # shellcheck source=src/php.sh
     . "$file"