new script docker-build to preconfigure parameters for docker build, set environment variable DOCKER_USER; fixed path in docker-update

README.md

@@ -25,3 +25,8 @@ docker-update
 -------------
 
 Script to update all or some images within declared in a yaml file. Use it to update the docker image of all or some services in your already deployed docker swarm stack.
+
+docker-build
+------------
+
+Script to be called from a directory with a Dockerfile to build the docker image. Tha name of the tag is derieved from environment variable `DOCKER_USER` and the path name. It automatically applies the options `--rm --force-rm`. As additional options, you can overwirte the image name as first parameter, and/or pass more `docker build` options.