There is no need to change any file. You can do so by navigating to admin/lists and set the Columns on Users page setting to 1.
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.