Add request read

bin/nexusbot.dart

@@ -151,7 +151,12 @@ If you have any issues, reply to this email.""",
 
                 return Response.found(settings.successUri);
               } catch (error, stackTrace) {
-                final message = "An error occurred: $error\n$stackTrace";
+                final message =
+                    """An error occurred for this request:
+${await request.readAsString()}
+$error
+$stackTrace
+                """;
 
                 try {
                   final room = client.getRoomByAlias(settings.adminRoom)!;