🚑 Persists precense database

Ref #1

happy-bubbles/rootfs/etc/cont-init.d/20-persist-db.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/with-contenv bash
+# ==============================================================================
+# Community Hass.io Add-ons: Happy Bubbles
+# Persists the presence database (and create if missing)
+# ==============================================================================
+# shellcheck disable=SC1091
+source /usr/lib/hassio-addons/base.sh
+
+if ! hass.file_exists '/data/presence.db'; then
+    hass.log.debug 'Starting Presence temporarly...'
+
+    cd /opt || exit
+    exec 3< <(./precense)
+
+    # Wait until the db exists
+    until hass.file_exists "/opt/precense.db"; do
+        sleep 1
+    done
+
+    # Just to be safe, wait another 2 seconds
+    sleep 2
+
+    # Kill it, if still alive
+    kill "$(pgrep precense)" >/dev/null 2>&1 || true
+
+    # Move the created database into a safe place
+    mv /opt/precense.db /data/precense.db
+
+    hass.log.debug 'Persistent precense database created'
+fi
+
+ln -s /data/precense.db /opt/precense.db