Add string.

en.json

@@ -218,6 +218,7 @@
         "failed_validation": "Failed to validate fields.",
         "database_error": "Database error.",
         "internal_error": "Internal error.",
+        "missing_permission": "Missing permission.",
         "unknown_error": "See console.",
         "operation_failed": "Operation failed.",
         "render_fail": "Template rendering failed.",