[projects/cleanbuild] Add instructions how to cleanup docker images

[glen]

commit 32459db7eb6a814f014e82db673160bcb9d84776
Author: Elan Ruusamäe <glen at delfi.ee>
Date:   Thu Apr 30 13:54:06 2020 +0300

    Add instructions how to cleanup docker images

 README.docker.md | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/README.docker.md b/README.docker.md
index 3df89db..6232a32 100644
--- a/README.docker.md
+++ b/README.docker.md
@@ -2,3 +2,11 @@
 
 With docker engine there's nothing needed to configure on local system other
 than access to running docker engine and docker client program.
+
+## Maintenance
+
+To kill all containers created by cleanbuild:
+
+```shell
+docker ps -f label=cleanbuild --format '{{.ID}}' | xargs -r docker kill -q
+```
================================================================

---- gitweb:

http://git.pld-linux.org/gitweb.cgi/projects/cleanbuild.git/commitdiff/32459db7eb6a814f014e82db673160bcb9d84776