This is a simple dislike button plugin for Wordpress. Because many websites and oblivious editors would benefit from it.
Copy the folder to your /wp_content/plugins folder, activate the plugin in the Wordpress backend and include the PHP snippet <?php dislike_button(); ?> where the button should appear in your theme.
The plugin uses cookies to store the visitors former actions. So far, this was only roughly tested well after midnight. Please let me know about any bugs!