[conf] add post repository update script file example

conf/packages/packages.db.post_update.sh.example

@@ -0,0 +1,38 @@
+#!/bin/sh
+# Entropy Framework 1.0
+# Entropy Client post repository update (equo update <repoid>) script
+# -- called every time repositories are updated --
+#
+# This is a sample file shipped with client repositories which contains
+# per-repository post repository update hook. More precisely, this script is
+# triggered when entropy updates repositories. As stated, this script is PER-
+# repository and it's shipped with it.
+# It MUST return 0, any different value will be considered as critical error.
+#
+# This script must be called with specific arguments explained here below:
+#
+#     # sh packages.db.post_upgrade.sh [REPOSITORY_ID] [ROOT] [ENTROPY_BRANCH]
+#
+# example:
+#
+#     # sh packages.db.post_branch.sh "sabayonlinux.org" "/" "5"
+#
+# PLEASE NOTE: this script is called automatically by entropy and, unless
+# requested otherwise, it should be NEVER EVER called by user.
+
+[[ -z "$3" ]] && echo "not enough parameters" && exit 1
+
+REPO_ID=$1
+ROOT=$2
+BRANCH=$3
+
+echo -e "
+>> Entropy repository post-update script
+>> Repository: "${REPO_ID}"
+>> Root: "${ROOT}"
+>> Entropy branch: "${BRANCH}"
+"
+
+exit 0
+
+### CUT HERE ###