Editing entry in front-end
Looks like you want to implement a feature to vote for entries. Have a look at these plugins, they make this really easy for you.


https://www.doublesecretagency.com/plugins/upvote
https://github.com/dukt/craft-like


If you want to implement something yourself, I would look into adding the button behavior using JavaScript, listen for click events and send the data over XMLHttpRequests to the entries/saveEntry controller.