NOTREADY readme update & permission mapping

dockerfiles/user-mapping.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+if [ -z "${USER}" ]; then
+  echo "We need USER to be set!"; exit 100
+fi
+
+# if both not set we do not need to do anything
+if [ -z "${HOST_USER_ID}" -a -z "${HOST_USER_GID}" ]; then
+    echo "Nothing to do here." ; exit 0
+fi
+
+# reset user_?id to either new id or if empty old (still one of above
+# might not be set)
+USER_ID=${HOST_USER_ID:=$USER_ID}
+USER_GID=${HOST_USER_GID:=$USER_GID}
+
+LINE=$(grep -F "${USER}" /etc/passwd)
+# replace all ':' with a space and create array
+array=( ${LINE//:/ } )
+
+# home is 5th element
+USER_HOME=${array[4]}
+
+sed -i -e "s/^${USER}:\([^:]*\):[0-9]*:[0-9]*/${USER}:\1:${USER_ID}:${USER_GID}/"  /etc/passwd
+sed -i -e "s/^${USER}:\([^:]*\):[0-9]*/${USER}:\1:${USER_GID}/"  /etc/group
+
+chown -R ${USER_ID}:${USER_GID} ${USER_HOME}
+
+exec su - "${USER}"