add db_sync helper script

helper_scripts/db_sync.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+# sync production db to local testing vm
+
+remote_host="vps2"
+local_host="lpb-air.local"
+
+echo "---------------------------------------"
+echo "sync aqi db from $remote_host to $local_host"
+echo "---------------------------------------"
+
+# download
+printf "\n  -> backup\n"
+ssh $remote_host 'docker exec postgres pg_dump -U aqi | gzip > backup.gz'
+printf "\n  -> download\n"
+rsync --progress -r --delete-after -e ssh $remote_host:backup.gz /tmp/backup.gz
+
+# sync
+printf "\n  -> sync\n"
+rsync --progress -r --delete-after /tmp/backup.gz -e ssh $local_host:backup
+ssh $local_host 'gzip -df backup/backup.gz'
+
+# replace
+printf "\n  -> replace\n"
+ssh $local_host "docker exec -i postgres psql -U aqi -c 'DROP TABLE IF EXISTS aqi;'"
+ssh $local_host "docker exec -i postgres psql -U aqi -c 'DROP TABLE IF EXISTS weather;'"
+ssh $local_host 'docker exec -i postgres psql -U aqi -d aqi < backup/backup'
+ssh $local_host "trash backup/backup"
+printf "\n  -> done\n"
+
+##
+exit 0