feat(shaarli): Add backups

Add restic backup functionality for shaarli data.

roles/shaarli/defaults/main.yml

@@ -7,3 +7,7 @@ shaarli_use_https: true
 
 # the subdomain link shaarli will be reachable under
 subdomain_alias: links
+
+# should we back up the data?
+shaarli_backup_enable: true
+shaarli_backup_cron: 0 45 3 * * *

roles/shaarli/templates/docker-stack.yml.j2

@@ -15,6 +15,23 @@ services:
     - data:/var/www/shaarli/data
     - cache:/var/www/shaarli/cache
 
+{% if backup_enable is not undefined and not false and shaarli_backup_enable is not undefined and not false %}
+  backup:
+    image: mazzolino/restic
+    environment:
+      - "TZ={{ restic_timezone }}"
+       # go-cron starts w seconds
+      - "BACKUP_CRON={{ shaarli_backup_cron }}"
+      - "RESTIC_REPOSITORY={{ restic_repo }}"
+      - "AWS_ACCESS_KEY_ID={{ restic_s3_key }}"
+      - "AWS_SECRET_ACCESS_KEY={{ restic_s3_secret }}"
+      - "RESTIC_PASSWORD={{ restic_pass }}"
+      - "RESTIC_BACKUP_TAGS=shaarli"
+      - "RESTIC_BACKUP_SOURCES=/volumes"
+    volumes:
+      - data:/volumes/shaarli_data:ro
+{% endif %}
+
 volumes:
   data:
   cache: