Use xmlstarlet

CloudronManifest.json

@@ -4,7 +4,7 @@
   "author": "Traccar developers",
   "description": "file://DESCRIPTION.md",
   "changelog": "file://CHANGELOG",
-  "tagline": "One-line description",
+  "tagline": "Modern GPS Tracking Platform",
   "version": "0.1.0",
   "healthCheckPath": "/",
   "httpPort": 8082,
@@ -22,10 +22,11 @@
     }
   },
   "website": "https://www.traccar.org",
+  "postInstallMessage": "file://POSTINSTALL.md",
   "contactEmail": "support@cloudron.io",
   "icon": "file://logo.png",
   "tags": [
-    "changeme"
+    "gps", "tracking", "seek", "fleet"
   ],
   "mediaLinks": []
 }