add another helper bash file

update_psa_helpers

@@ -0,0 +1,70 @@
+#!/bin/bash
+
+# if [ ${git_helpers_sourced:-1} = "1" ]; then
+#    readonly git_helpers_sourced=${BASH_SOURCE[0]}
+#else
+#    return 0
+#fi
+
+# Fetch/merge updates from predefined repository using git.
+# 
+fetch_customer_updates() {
+    local func="${FUNCNAME[0]}"
+    if ! pull_customer_repository customer_281; then
+        return 1 
+    fi
+    return 0
+}
+
+# Check if the fetched/merged files have the correct md5 and are
+# valid for the PSA.
+#
+check_new_customer_files() {
+    local func="${FUNCNAME[0]}"
+    return 0
+}
+
+# In case the new checked-out files are not correct, revert the git
+# repository to its previous state.
+#
+revert_customer_repository() {
+    local func="${FUNCNAME[0]}"
+    return 0
+}
+
+# Backup before the update-process. 
+#
+backup_previous_version() {
+    local func="${FUNCNAME[0]}"
+    return 0
+}
+
+# Try to install new opkg-packages (in case the are some
+# in the new git-checkout).
+#
+do_update_dry_run() {
+    local func="${FUNCNAME[0]}"
+    return 0
+}
+
+# Install the new packages using opkg. 
+#
+do_update() {
+    local func="${FUNCNAME[0]}"
+    return 0
+}
+
+# In case there was some error, re-install the previous package(s)
+# and use the backup to restore any conf/ini-files.
+#
+fallback_to_previous_version() {
+    local func="${FUNCNAME[0]}"
+    return 0;
+}
+
+# If all went well, then execute all necessary cleanup steps.
+#
+cleanup_previous_version() {
+    local func="${FUNCNAME[0]}"
+    return 0
+}