Docs: mention modification of HOST machine, and document destroy script

README.adoc

@@ -20,6 +20,9 @@ All you need to install Alpine Linux is just https://github.com/alpinelinux/apk-
 
 *Note*: If you use *GitHub Actions*, you’re better off using https://github.com/jirutka/setup-alpine[jirutka/setup-alpine] instead of this script.
 
+*WARNING*: This script must run as the root user, and it modifies the HOST
+system.  Run the generated `$CHROOT/destroy` script to safely remove the chroot
+it creates.  See `-h` text for details.
 
 == Requirements
 

alpine-chroot-install

@@ -21,8 +21,17 @@
 #   6. executes specified command or "sh" if not provided.
 #
 # Example:
+#   # Create chroot
 #   sudo alpine-chroot-install -d /alpine -p build-base -p cmake
-#	/alpine/enter-chroot -u $USER ./build
+#
+#   # Run ./build inside chroot
+#   /alpine/enter-chroot -u $USER ./build
+#
+#   # Safely destroy chroot
+#   /alpine/destroy
+#
+# WARNING: Do not run 'rm -rf /alpine' instead of /alpine/destroy.  It can
+# destroy parts of the HOST system, like /dev and the $BIND_DIR.
 #
 # Options and environment variables:
 #   -a ARCH                CPU architecture for the chroot. If not set, then it's