Mateusz Marchel

I think it could be stored as an option in database just like rss_secret and other stuff. Then in admin panel you can add text-box, so the user can input his own capability name. What do you think?

In wordpress we have roles and capabilities, right? For now every role which have edit_pages capability can view history – this is line 70 of your plugin index.php code. Also every role which have manage_options capability can view plugin config – this is line 73.
Now for viewing history i hardcode:
$this->view_history_capability = "view_history";
instead of
$this->view_history_capability = "edit_pages";
and add view_history capability to roles which i prefer.

My question is:
Are you planning to add this sort of customization possibility from plugin control panel?

I hope now is all clear. ??