better build scripts, CI + readme

Author: NorseGaud

build-docker.bash

@@ -1,12 +1,18 @@
 #!/bin/bash
-set -exo pipefail
+set -euo pipefail
+
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
-cd $SCRIPT_DIR/_ci
+cd "${SCRIPT_DIR}/_ci"
 docker build --no-cache -t anka-build-plugin --load .
-cd $SCRIPT_DIR
+cd "${SCRIPT_DIR}"
+
+# Optional extra Maven arguments (host env), e.g. MVN_EXTRA_ARGS="-DskipTests"
 docker run \
---rm --name anka-build-plugin -it \
--v ${SCRIPT_DIR}:/root/anka-build-plugin \
--v ${HOME}/.mvn:/root/.mvn \
--v ${HOME}/.m2:/root/.m2 \
-anka-build-plugin /bin/bash -c "cd /root/anka-build-plugin && mvn clean && mvn package"
+  --rm \
+  --name anka-build-plugin \
+  -v "${SCRIPT_DIR}:/root/anka-build-plugin" \
+  -v "${HOME}/.mvn:/root/.mvn" \
+  -v "${HOME}/.m2:/root/.m2" \
+  -e MVN_EXTRA_ARGS="${MVN_EXTRA_ARGS:-}" \
+  anka-build-plugin \
+  /bin/bash -c 'cd /root/anka-build-plugin && mvn -Daether.remoteRepositoryFilter.prefixes=false clean package ${MVN_EXTRA_ARGS}'