Add customAuth flag

CloudronManifest.json

@@ -24,5 +24,6 @@
   "memoryLimit": 524288000,
   "changelog": "file://CHANGELOG",
   "tags": [ "forum", "collaboration", "community", "discourse", "bb" ],
-  "postInstallMessage": "file://POSTINSTALL.md"
+  "postInstallMessage": "file://POSTINSTALL.md",
+  "customAuth": true
 }